UNITED STATES DEPARTMENT OF THE INTERIOR

BUREAU OF RECLAMATION

'.1.1horr.a.::: ,J • Rhone

PROGRESS REPORT I- -RESEARCH STUDIES ON

INLET AND OUTLET TRANSITIONS FOR SMALL CANALS

Hydraulic Branch Report No. Hyd-492

HYDRAULICS BRANCH

OFFICE OF ASSISTANT COMMISSIONER AND CHIEF ENGINEER DENVER, COLORADO

July 31, 1962

The information contained in this re -port may not be used in any publica­tion, advertising, or other promotion in such a manner as to constitute an endorsement by the Government or the Bureau of Reclamation, either explicit or implicit, of any material, product, device, or process that may be re­ferred to in the report.

CONTENTS

Purpose ........................... · .................... . C oncl us ions . . . . . . . . . . . . . . ................ , . . . . . . . . . ... . Introduction ............................... ~ ........... . Acknowledgment ....... · ...... ~ .............. • ........... . Test Equipment . ....... , ............................... . Investigation ........................................... .

Page

1 1 3 4 4 7

Open-channel Transitions . . . . . . . . . . . . . . . • . . . . . . . . . . . . . 7 Closed-conduit Transitions--Air Model Studies.......... 9 Combination Closed-conduit and Open-channel

Transitions ........................... ., . . . . . . . . . . . . 11 Closed-conduit Transitions - -Hydraulic Tests • • . . . . • . . . . 12

12- by 28-inch ·Transition . . • . . . . . . . . . . . . . . . . . . . . . . . 12 12- by 24-inch Transition . . . . . . . . . . . . . . . . . . . . . . . . • . 13 Square Inlet on 12- by 24-inch Transition • . . . . . . . . . . . 13

Figures

Typical Field Installation of a Broken-back Transition...... 1 Schematic Views of Test Facilities . . . . . . . . . . • . . . . . . . .. . . . . 2 Hydraulic Model and Instrumentation. . . . . . . . . . . . . . . . . . • . . . 3 Broken-back Transitions and Flow-spreading Humps . . . . . . . 4 Air Model Facilities for Testing Closed-conduit

Transitions· ............................... · . . . . . . . . . . . .. 5 Closed-conduit Transitions Tested on· Air_ Model . . . . . . . . . . . 6 Flow and Scour--Broken-back Transition-:--1:8 Slope,

6-inch Rise, Inlet Pipe Horizontal... . . . . . . . . . . . . . . . . . . . . 7 Flow and Scour--Broken-back Transition Modified with

Warped Surfaces--1:8 Slope, 6-inch Rise, Inlet Pipe on a· 2: 1 Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Flow and Scour--Broken-back Transition--1:8 Slope, 12-inch Rise, Inlet Pipe HorJzontal...................... 9

Flow and Scour--Broken-back Transition--1:8 Slope, 12-inch Rise, Inlet Pipe on a 2:1 Slope................... 10

Flow and Scour--30° Broken-back Transition--4-inch Rise, Inlet Pipe Horizontal . . . . . • . . . . . . . . . . . . . . . . . . . . . . . 11

Flow and Scour--25° Broken-back Transition--4-inch · Rise, Inlet Pipe Horizontal ... _... . . . . . . . . . . . . . . . . . . . . . . . 12

Flow and Scour--25° Broken-back Transition--4-inch Rise, Inlet Pipe on a 2: 1 Slope . . • • . . . . . . . . . . . . . . . . . . . . . . 13

Scour- -20° Broken -back Transition - -4-inch Rise . . . . . . . . • . . 14

CONTENTS- -Continued

Flow and Scour in Canal Protected by 4-inch Layer of 1-1/2-ihch Gravel--1:8 Slope. 6-inch Rise Transi-tion with Warped Walls and Horizontal Pipeline ........ .

Velo.city Distribution for Closed-conduit Transitions--Approach Pipe 6. 2D Long .....•... ~ ................. .

Velocity Distribution for Closed-conduit Transitions-­Approach Pipe 20 .. 4D Long ........•....... ; •.•.•.....

Draft Head at Inlet, and Loss Coefficients for Closed-conduit Transitions ............ -..................... .

Pressures on Closed-conduit Transition Walls ........ ~ •. Area Curves for Constant Height, Circular-to­

rec.tangular Transitions and for Conic Transitions •.••.. Combination Transitions Using Closed-conduit

and Open-channel Broken-back Sectiqp.s ...........•.... Flow and Scour- ..;Combination Closed-conduit

and Broken-back Transitions;..1:5. 5 Slope. 12-inch Rise. Inlet Pipe Horizontal ..••...••••••••.•...•......

Flow and Scour- -Combination Closed-conduit and Broken".'back Transitions with FloOJ!' Deflector ...•..•.•.

Sc'.our-'...Combination Closed-conduit and Broken-back Transition--1:5 .. 5 Slope. i2-inch Rise. Inlet Pipe on.2:1 Slope ... ·'~·.· ... · ................................ .

Flow and Scour..; -Combination Closed-conduit and Broken-back Transition Level Invert--Inlet PiPe on·2:1 Slope· ... ~-·.~ ................... •.• ....... .

Closed-conduit, Round-to-rectangular Transitions ...... . Scour--12;.. by 28-inch 1Closed-conduit Transitions--

Inlet Pipe H~riz~ntal. ,• . ! •• · •••••.••••••••••••••••••••••

Velocity Distribution and Loss Factors--12 by 28 TransitiOri ......................................... .

Flow in Canal with 12·:.. by 24-inch Closed-conduit Transition- -Inlet Pipe Horizontal ....•.....•...••••.••

Scour--12- by 24-inc;h Closed-conduit Transition--Inlet Pipe HorizOritai . ........... ~ ................... .

Flow and Scour--1i- by 24-inch, Transition--Inlet Pip.e Horizontal ....... ~ .............................. .

Velocity Distributions and Loss Factors. 12 by 24 Transition ......................................... .

Velocity Distribution and Loss Factors. 12 by 24 · Transition with Divider Pier .....••....•.•••••..•.•...

Table of Operating Conditions. and Performance Characteristics of Transitions ..••..•.•..•.•.•..•..•..

Effect of Submergence on Loss Coefficients •...••........ Loss Factors--12-inch Square to 12- by 24-inch

Figures

15

16

17

18 19

20

21

·22

23

24

25 26

27

28

29

30

31

32 ·

33

34 35

Transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

ii

·,

UNITED STATES DEPARTMENT OF THE INTERIOR

BUREAU OF RECLAMATION

Office of Assistant Commissioner and Chief Engineer

Division of Engineering Laboratories

Hydraulics Branch Denver, Colorado July 31, 1962

Laboratory Report No. Hyd-492 Compiled by: W. P. Simmons, Jr. Checked by: J. W. Ball Submitted by: H. M. Martin

Subject: Progress Report !--Research studies on inlet and outlet transitions for small canals

PURPOSE

Studies were made to determine erosion and energy losses produced in small canals by conventional open transitions from pipes to canals and from canals to pipes, and to develop more efficient and, if possi­ble, more economical designs.

CONCLUSIONS

1. The energy losses for conventional, broken-back, open-channel transitions discharging from pipes into small canals is O. 6 to O. 7 times the difference in velocity heads in the pipe and in the canal (Fig

2 2 ure 34). This velocity head difference, ~i -~; , is termed ~by.

2. Reasonable changes in angle of divergence of the sidewalls, and/ oof the slope of the invert of the open transitions, or of the attitude of the inlet pipeline, had little effect upon energy losses (Figures 4 and 34). .

3. Outlet losses were reduced to O. 4 b, hv and less, when short­closed conduit-expanding transitions were placed between the pipe­line and modified, broken-back transitions (Figure 21).

4. Outlet losses were reduced to O. 1 ~hv with 6D-long, closed­conduit transitions having circular inlets and rectangular outlets, and which discharged directly into the canal through a vertical head­wall placed normal to the canal axis (Figure 3A).

5. The addition of a dividing pier to decrease the structural span of the roof near the outlet of the round-to-rectangular transition increased

· the losses to about 0. 13 ~hv.

6. Changing the 6D-long transition to provide a square instead of the more difficult to form circular inlet increased the outlet losses to 0. 20 A hv, and the inlet losses to 0. 50 · Ahv,

7. Outlet losses of existing broken-back transitions can be mate­rially reduced by installing properly designed hoods within the. struc­tures to form controlled, closed-conduit expanding sections (Fig­ures 9C and 34).

8. Losses for inlet flows were about 0. 4 Ahv for all transitions tested (Figure 34). .

9. Scour or erosion in the loose sand of the canal bed was extensive with conventional, broken-back.transitions (Figures 7 through 15).

10. Selected humps or flow spreaders on the inverts within open transitions significantly reduced scour (Figures 7 through 15). The humps tested created a slight increase in head loss.

11. Scour was not appreciably effected by changes in the sidewall divergence or invert slopes of the open transitions.

12. Scour with the combination closed-conduit and open-channel transitions was less than for the conventional transitions (Figures 22 through 25).

13. Scour was reduced, .in most cases, when the pipeline to the tran­sition was on a 2: 1 slope instead of horizontal.

14. Scour with the 6D-long, closed-conduit transitions was about the same as with the combination transitions, and less than for the con­ventional transitions (Figures 27, 29, 30, and 31).

15. In general, scour was nominal with flow velocities of 4 fps in the 12-inch-diameter pipe, and severe with velocities of 6 fps. By scaling to larger structure sizes, according to Froude laws, these velocities are equivalent to 5. 7 and 8. 5 fps for 24-inch pipe, and 8 and 12 fps for 48 -inch pipe.

16. A 4-inch-thick layer of 1-1/2-inch gravel extending 4 feet down­stream from the transition of the 12-inch test installation provided excellent scour protection at the transition outlet (Figure 15). Ero­sion occurred beyond this blanket when the veloci~ies were high and/ or if waves were appreciable.

17. The optimum divergence of the sides of short circular-to­rectangular constant height, closed-conduit transitions is 7-1 / 2° relative to the centerline (Figures 6, 16, 17, 18, and 19). For longer transitions the divergence should be decreased to about 5° per side.

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18. For both inlet and outlet flows submergences up to 0. 25D over the crown of the pipeline at its junction with the headwall had only moderate effects upon head losses in the broken-back and the 6D­long closed-conduit transitions (Figure 35)8 Higher submergences tested in the broken-back transitions further increased the losses. Negative submergences. down to -0. 1 7D, which is tantamount to not having the transition full at the headwall, indicated only minor head loss increases for inlet or outlet flows.

INTRODUCTION

The Bureau of Reclamation's work in building irrigation distribution systems and related structures requires large numbers of transitionsfor pipelines which discharge into canals, and for canals that dis­charge into pipelines. When these transitions are small, as for instance with 48-inch or smaller pipes, the special forming required for warped transitions is usually not justified. In these cases, the broken-back-type transition made entirely of plane surfaces is used (Figure l).

In early designs of canal systems using broken-back transitions as V 2 Vc2

outlets from pipelines to canals, a loss value of 0. 3 <-if- 2g> was used. In this expression V p is fl.ow velocity in the pipeline and V c is velocity in the canal. This O. 3 loss factor was derived more or less intuitively and is apparently not supported by direc't experi-

V 2 Vc2 mental material. A similarly derived loss of O. 1 (~ - 2g )

was used when the transitions served as inlets from canals to pipe­lines.

'.

In recent years, there has been concern about the possibility of actual losses being greater than the 0. 3 and 0.1 values used in the early designs. If the losses were appreciably greater, the struc­tures could be restrictions in the distribution systems and reduce the carrying capacity to less than the design values. This would have serious effect upon operation of the irrigation system when the lands were fully developed. lt was. therefore, benevect impor­tant to conduct tests to determine the actual losses and to make any necessary changes in the design values. The investigations would be extended, as necessary, to obtain designs with lower losses.

A second important factor was the amount of scour or erosion in the canal immediately downstream from transitions when they were used as outlets. The effect of changes in the upward slope of the

3

transitiop. invert, or of the entering pipeline, or of the rate of diver­gence of the transition sidewalls on canal erosion were not known. Evaluation of these variables was necessary before design decisions could be made as to optimum outlet shape and canal bank protection requirements ....

The many different operating conditions and design modifications involved in the testing program dictated that the studies be conducted in a laboratory where such changes could be made easily and quickly. To fill this need, studies were inaugurated and are continuing on an intermittent basis in the Hydraulics Branch of the Division of Engi -neering Laboratories in Denver, Colorado. This progress report discusses the equipment ap.d procedures used in the tests and the results obtained to date.

ACKNOWLEDGMENT

The results achieved through this test program were the product of close cooperation between the staffs of the Canals Branch and the· Hydraulics Branch of the Assistant eommissioner and Chief Engi­neer's .Office in Denver. The data were obtained over a period of several years, and many engineers assisted in running tests, ana­lyzing data, and drafting portions of this report.

TEST EQUIPMENT

Most of the studies were made using a canal section contained within a wooden structure supported about 5 feet above the laboratory floor, and equipped with suitable piping and instrumentation (Figures 2 , and 3A). The canal bed was formed of loose plastering sand that eroded easily and showed scour effects within a short time. Canal invert widths of 12 and 18 inches were used, and the canal sides lay on 1-1/2:1 slopes. The canal invert was level in the direction. of flow. A template that rode on the top rails of the box was used as a guide for reshaping the canal bed between runs (Figure 3A).

In early studies the transitions were tested only as outlet strµctures with the flow passing from the pipeline, through the transition, and into the canal. The 12-inch-diameter pipe that supplied water to the trap.sition was placed level in part of the tests, and on a 2:1 upslope for other tests. The depth of flow in the canal w~s regulated by an adjustable tailgate at the downstream end of the model.

In later studies, the transitions were studied both as inlets and out­lets. The piping was modified so that in addition to the flow described above, water could be introduced into the canal from the tailgate end of the box to produce inlet flows into the transition and pipeline (Fig­ure 2).

4

Water leaving the test section was controlled by the tailgate when outlet flow tests were made,· and by ·appropriate valves in the piping system· when inlet tests were made;. The desired canal water sur­face elevations could the ref ore be maintained. : ·

The broken-back transitions were :c()rtstructed of. 3 / 4-inch plywood and were, treate<l to avoid excessive water absorption (Figure 4). In some cases. warped sections made of concrete were constructed within the confines of broken-back transitions (Figure 8). The closed-conduit transitions were usually made of 16-gage sheet steel with external reinforcing. as required, and with. 3/8-inch-thick steel upstream-and downstream flanges.

The rate of water flow supplied to the model was measured by cali -brated permanently installed Venturi meters in the central labora­tory water supply system.· Water was taken from the laboratory reservoir. pumped through the meters and the model. and returned to the reservoir for recirculation.

When a transition was used as an outlet. the pressure head in the 12-inch-diameter pipeline was measured at a station 1 foot (one­conduit diameter) upstream from the transition. When the transi­tion was used as an inlet, the pipeline head was measured at a station 15 feet (15D) downstream from the junction of the transition with the pipeline. The pressures were obtained by two piezometers, one on each side of the pipe on the horizontal centerline. The pres­sure leads were connected to 1-1 /2-inch-diameter stilling wells, and point gage measurements were made of the free water surfaces within the wells (Figure 3B). · The water surface elevations in the canal were measured by point gages 15 feet downstream from the junction of the transition with the canal for outlet flows. and 4 feet upstream from this junction for inlet flows (Figure 3C).

Throughout the test program difficulty was experienced in obtaining consistent and repeatable data because the quantities being deter­mined were small compared to the possible errors. Establishing water surface elevations was of primary importance and several procedures were used to accurately relate the reading of one gage to another. Best reemlts were· obtained by pooling the model to a 12-inch canal depth. and after allowing considerable time for tur­bulence and oscillations to cease, obtaining the gage relationships . When the higher rates of flow were studied, data were taken as soon as proper conditions were established and before extensive canal erosion occurred. Accurately determining the canal water surface was complicated by the·fact that submerged instruments like a Ser's Disc could not be used because it was necessary to repeatedly move the canal template up and down the model to reshape the bed. · A water surface point gage was used instead. and repeated

5

readings were.!made during ·a . .tes.t run -~o,get a good average figure for _the undulating. · wavy, or· choppy water surfaces. Small stilling wells w;orked sat-isfac,torily for ;the piezometer·readings for -th~. pipeline. Operator technique·,had,cooside-rabJ,e impact on the data, and with training and experience the accuracy aR.d consistency improved greatly~ . In spite .of -the-,effods and-precaution~ taken, the basic problem of:seeking smalLvalues in the midst of relatively large potential errors remained. : Therefore, the data presented herein may be ,accepted as representative, but minor va,.riations and scatter can be expected.

In the closed-conduit outlet transition tests, velocity measurements were made of the flow in the pipeline 1. 3D upstream from the tran- · sition inlet-and ·at -the transition exit (Figures 28, 32 and 33). For inlet. flows,· velocity traverses were made in the pipeline 1.-lD down­stream ,fr-om the -j.unction of _the transition with· the pipeline. A . 3-/ 16-inch-diameter total head. tube, was used for measurements in the , pipeline, and a 1/4-inch-diameter Prandtl-type Pitot-s-tatic tube was used for measurements at the canal end of the transition .

.. . ... Studies of: closed-conduit,expanding -outlet transitions were also made -with a test faeility using air as the. flowing fluid (Figure 5). Air was drawn from the -atmosphere through a 12-inch-diamet_er . pipe into the centrifugal blower. ,Jt then passed through a 10.14- -inah-:diamete-r pipeline into. the expanding ·transiti:on being tested, and back into the atmosphere. The 10. 14--inch-diameter.:pipeline was 63 inches long (6. 2D) for most of the tests. and was lengthened to-207°-inches (20.40) for.the rest. A piezometer located 4-:-1/2 Jnches from the outlet was used with the 6. 2D pipe. and tw.o dia­metric·ally opposed-wall taps locate_d: 1 diameter from the: outlet were used with the 20. 4D pipe.

Five expanding transitions made of light gage sheet metal were tested (Figures 5 and 6) .. - All had inlets 10. 14 inches in diameter, and alLwere 10,., 1,4 ,!inches high at. the outlet. The sidewalls expanded at the rates of 0°, 2-1/2°, 5°, 7-1/2°, and.10° relative to-the center;­line, and the lengths were 20. 28 inches. or 2D. One-sixteenth­inch'."diameter, pi~zometers were placed-along the centerline of the right sidewall- and along the invert, and also along the diverging . transition element from the 45° point above the invert of the cir­cular inlet to the lower .. right,-hand corner at th.a rectangular outlet (Figure 19F) •. · The piezome.ters were at stations 2, 5, 10, and 15 inches,from the transition inlet.·_. ·

. . .

Vertical and horizontal. centerline traverses were obtained near the_ transition inlets and at the o.utlets wi.th a l / 8 -in_ch,..diameter Prandtl­type. Pitot-static tube,\ "Pre·s,sur~s were. measured with water-filled U-tubes, and the readings were re:c-o~ded in tenths and hundredths

6 '

of an inch. Re·adings were taken after sufficient time had elapsed for conditions to stabilize after starting the flow. The Pitot-static tube was set at the desired position, the pressures read, and the tube moved to the next position. This process was repeated until the full effective length of the relatively short tube was within the conduit. The tube was then removed and inserted in the diametri -cally opposite station so the full length of each transverse could be covered. In addition to readings obtained with the Pitot-static tube, readings were taken of the head differential across the 9-inch­diameter inlet orifice on the 12-inch inlet line to the blower, and at the wall taps in the 10. 14-inch supply pipe. The barometric pressure and temperature were also measured so atmospheric den­sities could be computed.

INVESTIGATION

Open -channel Transitions

A number of open broken-back transitions were tested to determine the effect of upward slope of the invert. rate of sidewall divergence, degree of ·submergence over the outlet pipe crown. and slope of. the incoming pipeline on energy losses and scour in the canal chan­nel (Figures 4 and 7 through 15). In addition, the effect of placing humps on the transition invert to aid in spreading the flow, and the effects of other modifications like changing the sidewalls to modi­fied warped walls were tested. For convenience these designs, operating conditions, and test results are briefly summarized in Figure 34. Loss factors for all the broken-back transitions, includ­ing the ones modified with warped surfaces, were about 0. 5 to 0. 7 /;;. hv for outlet flows. The term ~hv equals the velocity head in

the pipeline 1 diameter upstream from .the transition, minus the velocity head in the canal 15 feet downstream from the transition.

T~e. flow patter~s thro~gh all the open tran~i~ions w~re generr:lly similar. If the mlet pipe entered the transition horizontally. the stream issuing from it tended to move straight through the transi­tion into the canal, and large eddies moved upstream well up into the transition along either side of the jet (Figure 7A). Scour on the canal bottom and on the side slopes was appreciable in the loose sand and a sandbar was built up across the canal 6 to 12 feet down­stream from the canal entrance (Figure 7B).

If the inlet pipeline was sloped, the stream issuing from it rose in the transition to the water surface to cause higher surface velocities and waves that scoured the canal slopes (Figure BA). Flow was nearly stagnate at the bottom of the transition and, in some cases. sand was deposited in the transition. A wide sandbar built up sev­eral feet downstream from the canal entrance (Figure BB).

7

Changes in the slope of the transition invert from a minimum of 1:13. l to a maximum of 1:5. 5 had no apparent effect on the losses encountered or on the. scour produced (Figures 34 and 7 through 15). Likewise, changes in divergence angles of the outer walls of the transitions from the minimum of 16° per side to a maximum of 30° per side had no appreciable effect, although limited data show a slightly lower loss for a 25° angle. Even altering the ot1,ter walls by constructing warped surfaces within the confines of the broken­back walls was not significantly effective ..

Different submergences above the crown of the pipe at its juncture with the transition showed little effect in early tests. More detailed investigations with the 20°, 25°, and 30° broken-back transitions showed lowest losses with small submergences, and progressively higher losses with submergences exceeding about 0.

11 pipe diameter 11

(Figure 35A).

Several "humps" were placed on the transition invert a short dis­tance downstream from the pipe exit to help spread the flow and obtain,smo9ther conditions with more uniform velocities.,at the ca_na~ entrance (Figures 4, 7C, 23B, and 23C). Improvements in flow conditions :and reductions in scour occurred, but the losses were either unaffected or increased. The usefulness of humps appeared to be restricted to reducing scour in the canal.

A qualitative measurement of riprap needed for controlling scour in the canal was obtained by placing a 4-inch·thick layer of 1-1 /2-inch gravel in .the first 6 feet of the model canal. Tests were made with the 1 :8 slope, 6-inch rise transition with warped walls and a horizontal inlet pipeline (Figure 15). A flow velocity of 3 feet per second in the pipeline failed to move any gravel or any appreciable amount of sand in the bed downstream. A 4-feet-per-second veloc­ity also failed to move the rock and .moved only a very small amount of sand. At a 6-feet-per-second pipeline velocity, the rock remained stable, but considerable erosion occurred in the sand farther down­stream (Figure 15C). It was apparent that this 1-1 / 2-inch rock was capable of protecting the model canal from scouring tendencies. By geometric scaling this rock is equivalent to 0. 125 times the ,pipe diameter. No tests were made with other sized rocks.

Noticeable reductions in head loss, improvements in flow distribu­tion, and reduction in scour were achieved when closed-conduit expanding sections were used in conjunction with the open transitions. A short submerged shelf projecting downstream from the transition headwall just above the pipeline crown in a 1 :8 sloping transition cut the loss factor from about 0. 6 to less than 0. 5 (Figure 34) .. A longer hood. that created a 4D-long closed-conduit within a 1:8 tran­sition and had a maximum divergence rate of 8-1 /2° per side reduced

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the loss factor to 0. 21 (Figure 9C). A short closed-conduit transi­tion from the 12-inch circular pipe to a 12-inch square section, inserted in the pipeline just ahead of the rectangular 1 :8 broken­back transition, reduced the 0. 6 loss factor to less than 0. 4. It was apparent that the best opportunities for improving transition performance lay in closed-conduit, gradually expandiil_g sections.

Closed-conduit Transitions--Air Model Tests

To determine the performance of a series of expanding closed­conduit transitions, air model tests were made (Figures 5 and 6) .

. The shapes of the transitions were selected after considering design problems involved in coupling them with open-type, but sh9rtened, transitions. To avoid excavations deeper than for present structures. no downward divergence relative to the centerline was used. Simi­larly, to avoid lowering the structure to maintain submergence over the crown of the conduit, no upward divergence relative to the center­line was used. Thus, the normal height of the section at the outlet was the same as at the inlet and equal to the diameter of the pipe -line. All divergence in the closed-conduit transitions occurred through divergence of the sidewalls and through the change in section from circular inlets to square or rectangular outlets.

Each transition was first tested on the 6. 2-diameter-long approach pipe, and velocity traverses were taken horizontally and vertically at the inlet and outlet (Figure 16). There was a slight distortion in the inlet velocity profile with the round-to-square transition. and the distortion became progressively greater as transition expansion increased. The outlet profiles showed that the flow expanded well and followed the diverging walls in the 0°, 2-1 / 2°, and 5° transitions and to a lesser extent in the 7-1 /2° transition. The 10° diverging section was too abrupt, and flow broke away from the right side and the upper and lower right corners so that reverse flow occurred.

It was believed that the somewhat distorted velocity distribution at the transition inlets had appreciable effect upon the ability of the flow to follow the expanding boundaries. A 12-foot extension was added to the approach pipe to produce a section 20. 4. diameters long and obtain a more fully developed and uniform distribution. Tests with the 0° divergence transition showed nearly symmetrical velocity distributions at both the inlet and outlet (Figure 17A). How­ever. tests with the 10° transition showed noticeable distortion in the horizontal traverse at the inlet, apparently due to the severe separation along the right side at the outlet. This separation was greater than the separation that occurred with the short approach pipe. It was concluded that regardless of the uniformity of approach conditions. the 10° transition was too abrupt to control the discharg­ing flow.

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Pressures were subatmospheric at the approach pipe wall taps just upstream from the transitions. This was expected and is due to the draft tube effect wherein velocity head of the entering stream is con­verted into pressure head as the flow expands and slows. The pres­sure level into which the transitions discharge is atmospheric, and hence the pressures in the approach conduit and upstream parts of the transitions where the flow is fast will be less than atmospheric. The extent of the subatmospheric pressure level is a direct measure of the effectiveness of the draft tube, or expanding transition. The draft head of the transitions, divided by the inlet velocity head, pro­duced dimensionless parameters which were plotted against degrees of sidewall divergence (Figure lSA). The greatest draft head occurred with a divergence of 7° to S0 and was 55 percent of the inlet velocity head.·

The loss in total head from the transition inlet to the atmosphere, divided by inlet velocity head, was similarly plotted against sidewall divergence (Figure lSB). This loss factor, K, was lowe~t for a divergence of 7. 5° to S0 and w::1.s 44 percent of the inlet velocity head. The pressures on the transition walls were negative with respect to the outlet head (atmospheric) in all cases except near the outlet of the 0° transition (Figure 19). The pressures at a given station became generally-more negative as the rate of transition divergence increased, until the 10° transition was :approached and the trend reversed. Flow separation occurred in this transition, and the effectiveness and efficiency dropped below that of the 7-1/2° one. _ In all cases, the lowest pressures were obtained on the transition element leading from a 45° point on the circular inlet to an outlet corner. These elements diverge more rapidly than any. others in the transitions.

Fo,:r comparative purposes, plots of cross-sectional areas versus distance along the transition are presented for the transitions tested and for conic transitions (Figure 20).

Loss coefficients, K, for conic expanding transitions of 2-1 /2° and 7-1/2° relative to the centerline, and discharging directly into the atmosphere, were found in previous tests to be .0. 273 and 0. 499 respectively, based on the inlet velocity heads. 1 / These values show a trend of greater loss with greater divergence to 7-1 /2°, instead of the decreasing loss shown by the round-to-rectangular transitions. This difference is explained by a comparison of the area curves of Figure 20 that show that conic sections enlarge much more rapidly than the rouhd-to..,rectangular transitions of the pre­sent study, and indicates that considerable separation, and hence loss, occurred in the 7 -1 / 2 cone. .This separation was found to exist in the turnout structure conic transition tests .

.!_/Report No. Hyd-365, "Hydraulic Model Studies of the San Jacinto­San Vicente Turnout and Metering Structure, San Diego Aqueduct Project, California. "

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Combination Closed-conduit and Open-channel Transitions

The relatively high efficiency of the closed-conduit expanding tran­sitions was partially exploited by placing 2D-long, round-to-rectangular transitions between the end of the circular pipeline and a shortened and modified broken-back transition (Figure 21). The height of the closed transition was kept the same as the diameter of the pipe and the sides diverged 7-1/2° relative to the centerline. The length was 2D and the outlet measured 12 inches high by 18-3/8 inches wide with an area 2. 8 times greater than at the inlet. A 5. 5D-long, upwardly sloping open-channel transition adapted the rectangular section to the trapezoidal section of the canal. ·

The loss coefficient for outlet flows was about O. 4 with the inlet pipe horizontal, and about O. 2 with it rising on a 2:1 slope (Figure 34). With the pipe horizontal, waves were smaller and less powerful than in previous transitions, but scour remained appreciable (Fig­ure 22). This was apparently due to flow from the closed pipeline continuing straight through the open transition along the floor with­out spreading or slowing down much .. Large back eddies were pre­sent at the sides in the open transition. Several humps were placed on the floor to "lift" this flow stream and help spread it. Scour was decreased when a 6-3/8-inch-high wedge-shaped hump was used, but remained almost unchanged with a 3-3/8-inch one (Figures 21 and 23). Better flow conditions occurred when the inlet pipe was placed on a 2:1 upslope (Figure 24). Wave action persisted, but flow was distributed more uniformly across the section upon reach­ing the canal. Considerable flow was present along the broken­b~ck transition invert, although the greater part of the flow was near the surface. The scour was moderate and the energy loss coefficient decreased to O. 21.

Additional tests were made with an open transition having a horizon -tal invert (Figures 21B and 25). The submergence over the crown of the closed-conduit outlet for a 15-inch (1. 3D) flow depth in the canal was O. 3D, as compared with 1. 3D for the sloped, open transi­tion. The tests were made with a 2:1 sloping pipeline. The water surface was somewhat choppy and waves carried into the canal to produce moderate bank erosion. The flow moving downstream extended completely across the water prism at the canal entrance, and from the water surface downward to 4 or 5 inches above the canal invert. The lowest layers of water were not in significant motion and bottom scour was not apparent. The loss coefficient decreased to O. 15, possibly due to the greatly decreased submer­gence at the outlet of the closed conduit.

11

Closed-conduit Transitions--Hydraulic Tests

The losses of the combined closed-conduit and open-channel transi­tions were significantly lower than for the usual open ones, and scouring was reduced. Consequently longer round-to-rectangular closed-conduit transitions that terminated in a headwall normal to the canal were studied (Figure 26). The water discharged directly through the headwall into the canal section for outlet flow tests, and through the headwall into the transition for inlet flow tests. No fur­ther transitioning was used. The closed-conduit transitions exploited the fact that more orderly and complete expansion, and hence slowing of the flow, can be obtained in closed conduits than can be obtained in the usual open-type transitions. Ideally, a two-thirds velocity reduction and about 90 percent of the velocity head can be recovered in a closed"".conduit transition 6 diameters long.

12- by 28-inch Transition. A closed-conduit transition with a 12-inch-diameter inlet, a 12-inch-high by 28-inch-wide rectangular outlet, and a length of 72 inches (6D) was· constructed and tested (Figures 2 and 26A). The transition sloped upward 4 inches and the top of the exit was to be level with or slightly beneath the normal canal water surface. The transition terminated in a vertical head­wall placed normal to the canal and the 12-inch-diameter inlet pipe -line was placed horizontal.

Relatively good flow conditions occurred near the headwall and in the canal. Conditions were similar to those shown in Figure 29. The least desirable conditions were present at a 15-inch flow depth· (1. 25D) where significant return eddies occurred along the banks at the water surface near the headwall. These eddies eroded the canal bank slopes noticeably (Figures 27B and 27C). At a 12-inch depth (1. OD) these eddies were small enough to be of little conse -quence and erosion was minor (Figure 27A). At a 10-inch depth (0. 8 3D) the eddies were not significant, but flow velocities along the canal banks and invert were higher than desired and erosion increased. The scours at the 0. 83, 1. 00 and 1. 25D depths com­pared favorably with those of the open, and the combination open­closed transitions.

Loss coefficients for the 12- by 28 -inch transition, when used as an outlet, were quite low and equal to O. 11, O. 09, and 0.11 for canal depths of 0. 83, 1. 00, and 1. 25D, respectively (Figures 28, 34, and 35). Loss coefficients when the transition was used for inlet service were O. 34, 0. 37, and O. 40, respectively. It was apparent that very low energy losses were obtained for outlet serv­ice, and that no penalty was incurred in erosion in the canal or in losses for inlet service.

12

Detailed studies of the flow conditions were made by velocity trav­erses across the inlet pipeline and the outlet portal (Figure 28). The measurements showed undesirable flow separation along the left side and the corners of the transition when it was used in outlet service. This indicated excessive divergence of the flow passage and a design unnecessarily expensive due to greater than required width.

12- by 24-inch Transition. A 6D-long transition with a 12-inch­diameter inlet and a lesser divergence rate to a rectangular outlet 12 inches high by 24 inches wide was constructed (Figure 26B). When used as an outlet it produced flow in the canal generally simi­lar to that obtained with the previous closed transition (Figure 29). Scour in the canal was relatively small at all flow velocities and water depths and comparable with the best of the other designs (Fig­ure 30). The loss coefficients decreased to 0. 09, O. 07, and 0.11 for the 0. 83, 1. 00, and 1. 25D flow depths (Figures 34 and 35). The reduced scour and lower losses attested to the excellent performance of the transition in expanding the flow, and veloctiy measurements at the outlet confirmed the conclusion (Figure 32).

The transition performed quite satisfactorily when used as an inlet. Good flow distribution was present in the pipeline, and loss coeffi­cients of O. 35 were determined for canal depths of 1. 00 and 1. 25D (Figures 32, 34, and 35). These losses compared very favorably with those of all other designs.

It was recognized that field installations might require transitions so large that the flat tops near the head wall would pose structural problems. This would be less complicated if the. span were cut in half by using a center supporting wall or pier. To determine the effects of such a pier on the flow and losses, tests were made with an 18-inch-long pier in the transition (Figures 26, 33, 34, and 35). The pier was O. 2D thick and had a rounded end inside the transition and a blunt face at the exit end. Its presence increased the outlet loss coefficients to O. 10, 0. 12, and O. 17, and the inlet loss coeffi­cients to O. 39 and O. 40. A part of this increased loss is- undoubtedly due to the more distorted velocity distribution that occurred in the te_sts with the pier present (Figure 33). When this increased dis­tortion was first noted the pier was suspected of being out of aline -ment. A check of the alinement showed it to be satisfactory, and it appears'that the pier can aggravate a moderate distortion into one of greater magnitude. ·

Square Inlet on 12- by 24-inch Transition. Consideration of the cost of forms to make round-to-rectangular transitions led to questioning whether or not simpler square-to-rectangular designs

13

would perform satisf-actorily. Therefore, a •6D-long transition with a 12-inch--square inlet instead of a round one,. and a 12- by 24-inch rectangular outlet was te·sted (Figttre ·2:sc).. The loss: coefficients for outlet flows were O. 20, O. 20, and O. 23 for depths of O. 83D, 1. 00D, and 1. 25D. These values represent about a 100 percent increase over those obtained w-ith the circular entrance design. For inlet-type flows, the loss coefficients were O. 50, O. 50, and O. 51 (Figure 36). These values -are about 25 percent higher than for the circular inlet transition.

In terms of actual head loss in a prototype structure at flow veloc­ities of 8 feet per second, the outlet losse:s for the square-to­rectangular transition are only about O. 10 feet of water more than for the round-to-rectangular design. In many instances this small additional loss may be insignificant, and the lesser construction cost. of the _square-to-rectangular transition will dictate its use.

14

Siphon outlet at Station 521, West Lateral Rogue River Basin Project, Oregon. November 1961.

CANAL INLET AND OUTLET TRANSITIONS

Typical Field Installation of a Broken-back Transition

Figure 1 Rep_ort Hyd 492

'"

A

FIGURE 2 REPORT HYO. 492

Transition-.\

_,k-~--1--1 1--_--:.._-+_-........ ..:-~-====~:'.:'.::J __ 0

'----------------------------------1c,-

PLAN

1-<---------- -- ---18'-6" - --- ----- ----- __ ,,, I I I I

_:.-._-:::::::::-_::·.:,-,._.:_::":;.-·:_:· _ _._:.-.:.:-::/-:;:.:

x

( Adjustable \ toilgote

Sond bed/ Perforated /, baffle - /

--12" L.W. Pipe

D

D

Reservoir ELEVATIOfll

TO OPERATE AS AN

INLET TRANSITION OUTLET TRANSITION

CLOSE C,D A, B

OPEN A,B C, D

SECTION B-B TABLE OF VALVE POSITIONS FOR

INLET AND OUTLET FLOWS

CANAL INLET AND OUTLET TRANSITIONS SCHEMATIC VIEWS OF TEST FACILITIES

A. Canal model with template in place for shaping sand bed. Closed conduit transition installed with horizontal approach pipe.

Figure 3 Report Hyd 492

B. Stilling wells and point gages for determining hydraulic grade in 12-inch pipelir ·.

C. Point gage for determining water surface elevation in canal.

CANAL INLET AND OUTLET 'I'RANSITIONS

Hydraulic Model and Instrumentation

J

J

PLAN

,.... ______________ , ... o· ----------------ao4 ' '

,--r--.-1 I I I

;' .! .... I _1

' .. ,--.• I j •• I

~-t- A

-t : ' ' ' I •,., I

' I ..,, I I I I __ Ll

I '"''"'f ' "!!

' 1--i ~

~ ________________________ j"

-.,- SECTION A-A

A. 1•8 SLOPE, 12 INCH RISE

--r-r •' I !!! '

--i ~ .. -· 2 ... j ' ' -¼-+- A

'+ : --t i ., ' !!! ' I o

...... i ... .i

12 inch light ~--~-------4'-4• ---------~

~--~~~r --. +---~; !!!!!

SECTION A-A

E. 20° DIVERGENCE, 4 INCH RISE

CANAL

Al

PLAN

,--"l--.-' ' I I .. "'"' -..:.~ : I

--.i : j !!! I

- ;--,- A

1--~ :

' I I I . ' "'I _, .. ' ' ' ' I __ LI..

k,,,------,-o· ------ :,,,I

' ' --------:::..,· --r "!!

t=- lk,f _L __________ -:::[* e!(!! .. SECTION A-A

8. 1:8 SLOPE, 6 INCH RISE

J

12 inch light weight pipe,

PLAN

~----- t- o·-~--:

--1,--c •' ' ~N•I !! ..

--.t 7 A ~-LJA : I

,--t ' !.iN: !! I ' I __ LL

I di ---11---!

I 11:Sf --- ----=D~t SECTION A-A

C. 1:8 SLOPE, 4½ INCH RISE

12- INCH CANAL INVERT WIDTH 4

Al

-TT . ' !!! I

1 -~

1--;t{ ___ _ll_41

01 -, I I

!? : ' I , __ t_j_

12 inch li9ht ;... ............... 3,_ 4.!.~-----~

~ .. ' ... --,

~--i SECTION A-A

F. 25 ° DIVERGENCE, 4 INCH RISE

J

--r-r ~:

--i :';' !! ":" A

' I j -.f-t- A

1--4 : ' I . ' !!! I

__ j_j ~c

B -----2'-eL:i, __ {

.. -----------.J !!?ire

B ., SECTION A-A

--r 'b

--l 1--,

G. 30° DIVERGENCE, 4 INCH RISE

20-INCH CANAL INVERT WIDTH

INLET AND OUTLET TRANSfTIONS

~--f ~ ' _J

·zu~ I I •_.. \ \o 'j"

\ \ __ 1. ' ' \ --11f -----" ~--

0. HUMP USED IN. 1•8 SLOPE, 6 INCH RISE TRANSITION

SECTION C-C

ffi: 12"7 ____ ~

bi!!~ .. 7 __ t '

I .~~,---... --~ 1• I 11,

4 i ..... 1: . -;1c-1f SECTION B-B

TYPICAL SECTIONS

BROKEN-BACK TRANSITIONS ANO FLOW SPREADING HUMP

:;.,. .. _ iilG> -tc: :'j:U !'"1

:=_.

·,

Air was drawn from the atmosphere, through the measuring orifice, and then through the outlet transition.

CANAL INLET AND OUTLET TRANSITIONS

Air Model Facilities For Testing Closed-conduit Transitions

Figure 5 Report Hyd 492

.. ,

12 Gage Inlet Range to match lo" pipe -- ,

FIGURE 6 REPORT HYD. 492

', ,22 Gage Sheet Metal

IOJ4'1.D.Pipe &.2ond '~/ . r--·16Goge Outlet Flange 2" wide 20.4diometers long._ ,..-------------1-n--l--'-------==,.jj··

---c E\.QW. __ >- --o- FREE DISCHARGE TO ATMOSPHERE FR0II CENTRIFUGAL BLOWER O..._ _________ _

ELEVATION

TYPICAL ARRANGEMENT

f------- 20.28"------~

i.. _E!:QlY_. ~-;!f r-m .... d +

L_ l---10.14!!."

PLAN SECTION A-A

NO DIVERGENCE ( On Each Side)

A½.= 1.27

J-:!! T L-1-,.~-=-1

PLAN

5° DIVERGENCE ( On Each Side)

l+-10.14~--l

SECTION C-C

A¼,= 1.72

t+------20.28"------>fE .

I _f_L_QY.t._ -<

:L

PLAN

10° DIVERGENCE ( On Each Side)

rm = ! a; . T -~ -L-

PLAN

l+-10.14'~.,..j

SECTION B-B

1• 22 DIVERGENCE ·

.(On Each Side) A¼= 1·50

.... :.i D

r : =~ ,ri

T .L-r:F---t----"I

l----10.14"-+!

PLAN SECTION D-D.

~--10.14~-..l SECTION E-E

A¼,= 2.17

1½° DIVERGENCE A¼,, 1.94 ( On Each Side)

CANAL INLET AND OUTLET TRANSITIONS CLOSED-CONDUIT TRANSITIONS TESTED ON AIR MODEL

is confined mainly to passage center. Eddies occur at sides. Q = 3. 0, Vp = 3. 8, canal depth = 1. 5D.

Figure 7 Report Hyd 492

B. Scour after 45 minutes operation. Q = 3. 0, Vp = 3. 8, depth = 1. 5D.

C. Scour 75 minutes operation with hump. Q = 2. 4., Vp = 3. 0, depth = 1. 5D.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Patterns--Outlet Flows Broken-back Transition, 1:8 Slope, 6-inch Rise

Inlet Pipe Horizontal

A. The surface is turbulent with Q = 3. 1 cfs, Vp = 4. 0 f / s, depth = 1. 3D. A boil occurs near the headwall.

B. Scour after 1 hour operation. Q = 2. 4 cfs, Vp = 3. 0 f/s, depth= 1. 3D. Sand was deposited in the transition.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour- -Outlet Flows Broken-back Transition Modified with Warped Surfaces

1:8 Slope, 6-inch Rise. Inlet Pipe on 2:1 Slope

Figure 8 Report Hyd 492

A. The water surface is mildly turbulent. Q = 4. 7 cfs, Vp = 6. 0 f/s, depth= 1. 3D.

Figure 9 Report Hyd 492

B. Scour after 1 hour operation. Q = 4. Vp = 6. 0, depth = 1. 3D.

C. Scour after 45 minutes operation with hood installed in transition. Q = 4. 7, Vp = 6. 0, depth = 1. 3D.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Patterns--Outlet Flows Broken-back Transition, 1:8 Slope, 12-inch Rise

Inlet Pipe Horizontal

A. The water surface is somewhat rough. Q = 4. 7, Vp = 6. 0, depth = 1. 3D.

B. Scour after 1 hour operation. Q = 4. 7, Vp = 6. 0, depth = 1. 3D.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Pattern--Outlet Flows Broken-back Transition, 1:8 Slope, 12-inch Rise

Inlet Pipe on 2:1 Slope

Figure 10 Report Hyd 492

A. Mildly turbulent water surface. Q = 2. 4, Vp = 3. 0, depth= 0. 8D.

B. Scour after 25 minutes operation each, with flow velocities in pipeline of 2, 2. 5, and 3 f/ s. Depth = 0. 8D.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Pattern - -Outlet Flows 30° Broken-back Transition, 4-inch Rise

Inlet Pipe Horizontal

Figure 11 Report Hyd 492

A. Mildly turbulent water surface. Q = 2. 4, Vp = 3. 0, depth= 0. SD.

B. Scour after 30 minutes operation each at flow velocities in pipeline of 2. 2. 5. and 3 f/s. Depth = 0. SD.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Pattern - -Outlet Flows 25° Broken-back Transition, 4-inch Rise

Inlet Pipe Horizontal

Figure 12 Report Hyd 492

A. Turbulent water surface. Q = 2. 4, Vp = 3. 0, depth= 0. 8D.

B. Scour after 30 minutes operation each

at flow velocities in pipeline of 2, 2. 5, and 3 f/s. Depth= 0. 8D.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Pattern - -Outlet Flows

25° Broken-back Transition, 4-inch Rise Inlet Pipe on 2: 1 Slope

Figure 13 Report Hyd 492

A. Scour after 2-1/2 hours, Vp = 2) 2. 5, and 3 f/s; ca.nal depths of 8, 10, and 12 inches. Pipeline horizontal.

B. Scour after 2-1/2 hours, Vp = 2, 2. 5, and 3 f/s; canal depths of 8, 10, and 12 inches. Pipeline on 2: 1 slope, depth= 0. 8D. ·

CANAL INLET AND OUTLET TRANSITIONS Scour Patterns--Outlet Flows

20° Broken-back Transition, 4-inch Rise 20-inch Canal Invert

Figure 14 Report Hyd 492

Figure 15 Report Hyd 492

A. Flow conditions. Q = 2. 4, B. Flow conditions. Q = 4. 7, Vp = 3 f/s. Scour was negligible. Vp = 6 f / s. Scour occurs at end

of riprap.

C. Scour after 1 hour at Q = 3. 1 cfs, Vp = 4 f/s and 1 hour at Q = 4. 7 cfs, Vp = 6 f/s, canal depth = 1. 3D.

CANAL INLET AND OUTLET TRANSITIONS

Flow and Scour in Canal Protected by 4-'inch Layer of 1-1/2-inch Gravel. 1:8 Slope, 6-inch Rise Transition with Warped Walls and Horizontal Pipeline--Outlet Flows

...

1.0 LEFT i---

0.8

0.6

0.4

0.2

AICIH 0 0.8

1.0 I.._

0.8

0.6

0.4

0.2

0 0.8

-- TOP I"--. - r,,...

1.0 ~...;:: ~

""1"

~ 0.8

' 0.6

• 0.4

~ I>

L, 0.2

.... :.,"' I BOTTOM _.,,.,, l.-'

1.0 1.0

'"\ ~

0.8 0.8

' 0.6 0.6

1,fL 1./L . 0.4 0.4

! 0.2 0.2

JI

-~

~ :fl'

.-

FIGURE 16 REPORT HYD. 492

~~ 0

\

I ~-,,

0.9 1.0 I.I 0 0.8 1.0 1.2 1.4 0.9 1.0 I.I

0 0.8 1.0 1.2 1.4

V/ VAVG. (ENTRANCE I Y/vAvG. (EXITI V/y/NG. (ENTRANCE) Y/yAVG. (EXIT)

A. 10.14" x 10.14" OUTLET (0°) 8. 10.14" x 11.91" OUTLET (2Ve0 )

1.0 1.0 ;....-.:::-N.. ~ ~- -,,.. r-,, ,,,_ ~ ~ ' ~

0.8 "'ll' -....... '- '\,

' 0.8

- I--

l-'t_

0 ~ 0.6

) ~--0.6

C p .,~-

0.4 0.4 0 -,-- -

' t J ./

0.2

P' 0.2

j r

)

:...-~ ~ ~ ~J...--11' ,/' -

0.9 1.0 I.I 0 0.8 1.0 1.2 1.4

0 0.8 0.9 1.0 I.I 1.0 1.2 1.4

V/yAVG. (ENTRANCEI Y/yAVG. (EXITI V/yAVG. (ENTRANCEI V/ VAVG. (EXIT)

C. 10.14" x 13.69" OUTLET ( 5°) 0. 10.14" x 15.48" OUTLET (7'12°)

1./L

1.0 -0.8

0.6

0.4

0.2

0 0.8

;-,,- --r--~ ~ 'I

0

' • -,-

' -,-

-p

I l_,,i

,_

~ ~ ~ 0.9 1.0 I.I

. V/vAvG. (ENTRANCEI

1.0 --r- -a....

' 0.8

- ......... ,.._ "'~~

J 0.6

,_,_ ~

0.4 ;

h 0.2

~ - I a --....,,.,,.-./

/'

...,,..... -a-~

0 0.8 1.0 1.2 1.4 1.6

V/yAVG. (EXIT)

E. 10.14" X 17.30" OUTLET ( 10°)

EXPLANATION

-Horizontal traverse -vertical traverse Inlets of all transitions 10.14" Oiometer Divergence angle is measured relative

to the conduit centerline.

CANAL INLET AND OUTLET TRANSITIONS VELOCITY DISTRIBUTION FOR CLOSED-CONDUIT TRANSITIONS USED

AS OUTLETS - APPROACH PIPE 6.2 D LONG AIR MODEL TESTS

··- El.GU-RE-- 17 REPORT HYO. 492

LEFT ~L I :S'\

~ , I

li I

id 1.0 l..d::l!e!!~:r:__J _ _L~~~ ~

0.8 .

¼.

0.9 1.0

V/v~VG. ,. ENTRANCE ·

0.9 1.0

V/VAVG. ENTRANCE

I.I 0.8 1.0 1.2 ·1.4

V/v AVG.

EXIT

1.6 1.8

A. 10.14 11 x 10.14 11 OUTL-ET (0°)

I.I

--LEFT "

~~- ..

--__;----~

0'"""" RIGHT. --

0.8 1.0 1.2

~ ..,~

~ 0

~ ~ a

_..~a

.d""' ~ j

~

.L~ v1. .. tVAVG. EXIT

/ __ .,,,,..

1.6 1.8

8. 10.14 11 x 17.30 11 OUTLET (10°)

lnlets of both transitions 10.14" diameter o - H·arizontal traverse a - Vertical traverse

TOP

BOTTOM

2.0

TOP ..

BCl'fTOM

2.0

CAN AL ·INLET. AND OUT LET TRANSITIONS VEL'OCITY DISTRIBUTION FOR _CLOS£D-CONDUIT TRANSITIONS USED

A S OU T L E T S A P P R O A C H P I P E 20. 4 D LO N G AIR MODEL TESTS

581

581

8 -0.6 <( LU z t-t--0.5 IL LU <(J a:: z O - -0.4 ...... LU<(

Jo

YI /'

/,

~ -

FIGURE 18 REPORT HYO. 492

I ...._,,

I.

z <1:-0 3 - LU , L-;,,,,,' ... ::c <( >-~ t:-0.2 LUO ::c 0

J LU

~> -0.1 ::::, fl) fl)

o -6.2 DIAMETER -LONG APPROACH PIPE LJ. -20.2 DIAMETER- LONG APPROACH PIPE

~ 00 ll.

2 4 6 8 10 SIDEWALL DIVERGENCE RELATIVE TO t. (DEGREES}

0.8

0.7 ~ .. .... z w 0

lJ... lJ... 0.6 w 0 0

(/) (/)

0 J 0.5

I

I 6.

A. DRAFTHEAD AT INLETS-VS-RATE OF EXPANSiON

o -6.2 DIAMETER -LONG .APPROACH PIPE A-20.2 DIAMETER-LONG APPROACH PIPE

I I I I I I

\ I I I I I I

K= HEAD DROP FROM TOTAL INLET HEAD TO ATMOS. VELOCITY HEAD AT INLET

'

"' I"' A

~ ~ :-----..... _,,,,)

~

I 2 4 6 8

SI DEWALL DIVERGENCE RELATIVE TO It, (DEGREES) 8. LOSSES -VS-RATE OF EXPANSION

Trans it ions discharge directly into atmosphere Transition outlets 10.14 inches high

CANAL INLET AND OUTLET TRANSITIONS DRAFT HEAD AT INLET AND LOSS COEFFICIENTS FOR CLOSED- CONDUIT TRANSITIONS USED AS OUTLETS

AIR MODEL TEST

10

FIGURE 19 : REPORT HYO. 492

a: "' ..

-0.6

-0.-5

~ ~ -0.4

0 "' N:,:

"' - >-.... 1- U --o.s .. 3 0 "' .. > "' :c ~ -0.2

t! .. a: o -0.1

a: "' ..

0

-0.6

-0.5

~ ~ -0.4 0"' N:,:

"' - >-.... t- g -0,3

.. ..J

0"' .. > "' :c ~ -0.2

.. ..J

... :!: .. a: o -0.1

a: "' ..

0

-0,6

-0.5

~ :;: -0.4

0 "' N:,:

"' - >­.... t- 0 -0.3 .. 3 0"' .. > ~ ~ -0.2

.. ..J

... :!: .. a:· 0 -0.1

0

PIPELINE --TRANSITION -\\ OUTLET -

--o ------·

' Is.

' .. ' '¾ ~ ""l>i,,

-o.4 o o.4 o.e 1.2 1.s 2.0 DISTANCE FROM INLET

INLET DIAMETER

A. 10.14" x 10.14" OUTLET (0°)

-0 ~-:--- l PIPELINE \ - ,

\ OUTLET -

\\-_

'~ -~ ~.TRANSITION ~ r-...

~

-0.4 0 0.4 0.8 1.2 1.8 2.0 DISTANCE FROM INLET

INLET DIAMETER

C. 10.14" x 13.69" OUT.LET (5°)

--o ------ H

Pl PE LINE ,

--l

' ' OUTLET

. ..._

~ ...,_TRANSITION

'~

-0.4 0 0.4 0.8 1.2 1.6 DISTAN·CE FROM INLET

INLET DIAMETER

E. 10.14" x 17;.30" OUTLET (10°)

-0.6

-0.5

a: "' .. "'0 2 ,ct -Q.4 ·o"' N:,:

"' - >-.. .. t- 0 -o., ~g 0"' .. > ~ ~ -0.2 .. ..J ... :!: .. a: O -0.1

a: "' ..

0

-0.6

-0.5

; ~ -0.4

0 "' N:,;

"' - >-.. I-I- g -0.3 .. ..J ., "' .. > ~ ~ -0.2

I- ..J ... :!: ... a: 0 -0,J

0

I -PIPEL!!L_

--0 ... ______ \

-

\l OUTLET=

' ~ 1,c.TRANSITION

., ~~

-0,4 0 0_4 0.8 1.2 1.6 2.0

DISTANCE FROM INLET INLET DIAMETER

8. 11.l4"x 11.91" OUTLET (21/2°1

----- \ ·. PIPELINE \ --··

\ OUTLET -'\ \

TRP.NSITION ''~ ' -0,4 0 0.4 0.8 1.2 1.8 2.0

DISTANCE FROM INLET INLET DIAMETER

D. J0.14" x 15.48" OUTLET (7 1/2°)

SECT ION AA

EXPLANATION . ----- l Of side)l'oll

-·--<>-·- 46' Element. -t Of bottom Divergence angle measured

relative to conduit centerline

12 Piezometers in each transition

PIEZOMETER STATIONS:

1/ 14 , 0.1973 D

1/ 14 , 0.493 D

11\°i4 , 0.986 D

1~~4 , 1.480 D

F. TYPICAL PIEZOMETER LOCATIONS

CAN A.L INLET AND OUTLET TRANSITIONS WALL PRESSURES ON CLOSED-CONDUIT TRANSITl,ONS USED

AS OUTLETS -APPROACH PIPE 6.2 D LONG AIR MODEL TESTS

581

Fl GURE 20 REPORT H YD 492

.... LL.I 1.4 LLJ LL.

2 4 6 8 10 12 14 16 18 20 22 DISTANCE ALONG TRANSITION <t_ (INCHES)

A. CIRCULAR-TO-RECTANGULAR TRANSITIONS WITH CONSTANT HEIGHT

1.8 ------------.--.....---~-----.---.---..------.---....-----,

1.6 ----------;----+---,------t---t----r------+--

.... LL.I 1.4 l----+----+-----1---+---+----+---+---+-./---+---+-----; LL.I LL.

~ 1.2 < => o. (/) 1.0 l----+----+-----1---1---.... "'r-----t----:::,_,,-:;;..-.---+----+---=-~

< LL.I a:: < 0.8 I-----+---+---~

0.4 ----------------------~-----------------------0 2 4 6 8 10 12 14 16 18 20 DISTANCE ALONG TRANSITION <t_ (INCHES)

B. CONIC TRANSITIONS

CANAL INLET AND OUTLET TRANSITIONS AREA CURVES FOR CONSTANT HEIGHT, CIRCULAR-TO­

RECTANGULAR TRANSITIONS, AND FOR CONIC TRANSITIONS

22

FIGURE 2.'I REPORT HYO, 4

Stondord 12'Flonge...._ A 12' Pipe.,

2 Piezometer Taps__.,., ·

PLAN S·ECTION C-C

---·2l----,.--------sar-----,-----<6'------------

SECTION A-A SECTION S-S

A. 7f ° CLOSED AND f:5.5 SLOPED, 12 INCH RISE ·OPEN TRANSITION

Standard 12'Flange, A 12' Pipe\ '•

PLAN LARGE HUMP

0--"A 1· I ' I I ,I :.i- ... ,.

!: : ' ' t_ :

. __ J

SECTION A-A

B. 7½° CLOSED AND HORIZONTA'L OPEN TRANSITION SMALL HUMP

G. HUMPS

.CANAL INLET AND OUTLET TRANSITIONS COMBINATION TRANSITION 1:JSING CLOSED- CON-OUIT AND OPEN CHANNEL

BROKEN BACK SECTION -WITH AND WITHOUT HUMPS

A1 Water surface is mildly turbulent in transition, but smooth in canal. Q = 4. 7, Vp = 6. 0, canal depth = 1. 3D .

B. Scour after 1 hour operation. Q = 4. 7, Vp = 6. 0, canal depth = 1. 3D:

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Pattern--Outlet Flows Combination Closed-conduit and Broken-back Transition

1:5. 5 Slope, 12-inch Rise. Inlet Pipe Horizontal

Figure 22 Report Hyd 492

A. A hump occurs in the water surface above the Design 2, hump-like deflector on the floor. Q = 4. 7, Vp = 6. 0, canal depth= 1. 3D.

Figure 23 Report Hyd 492

B. Scour after 1 hour operation 6-3/8-inch-high deflector. Q=4.7, Vp= 6.0f/s.

C. Scour after 1 hour operation 3-3/8-inch:..high deflector. Q = 4. 7, Vp = 6. 0 cfs.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Patterns--Outlet Flows Combination Closed-conduit and Broken-back Transition

With Floor Deflector 1 :5. 5 Slope, 12-inch Rise. Inlet Pipe Horizontal

A. Scour after 1 hour. Q = 3. 1, Vp = 4. 0, canal depth = 1. 3D.

B. Scour after 1 hour. Q = 4. 7, Vp = 6. 0, canal depth= 1. 3D.

CANAL INLET AND OUTLET TRANSITIONS

Scour Patterns- -Outlet Flows Combination Closed-conduit and Broken-back Transition

1:5. 5 Slope, 12-inch Rise. Inlet Pipe on 2:1 Slope

Figure 24 Report Hyd 492

A. Somewhat turbulent water surfaces occur in the transition and canal. Q = 4. 7, Vp = 6. 0, canal depth = 1. 3D.

B. Scour after 1 ho~r operation. Q = 4. 7, Vp = 6. 0, canal depth = 1. 3D.

CANAL INLET AND OUTLET TRANSITIONS

Flow Conditions and Scour Pattern - -Outlet Flows Combination Closed-conduit and Broken-back

Transition--Level Invert--Inlet Pipe on 2:1 Slope

Figure 25 Report Hyd 492

.. ,

PLAN SECTION B-B

t<----------- 5'-11' -~------~

! . 4 ,.·c•..,·, : g +-; ~ ::::dtt½; -~~

SECTION A-A -<{

rES-.N +

i __ . :. ___ 2a· __ j

SECTION C-C

A. 12 INCH ROUND-TO-12x28 INCH RECTANGLE

~ PLAN • • E i--------- s-11 ----- ------1

. : --==--..., ~~~) I . l +~ r~--~:=J E •

SECTION A-A

SECTION 0-0

SECTION E-E

8. 12 INCH ROUND-TO-12x24 INCH RECTANGLE

.lf----l=L----Jt _.J PCAN l_j

F r- ·--------s· 11·- ________ j I 4

12·~) l ' =l l= i- -------~---- -~~~1

G SECTION A-A

SECTION F-F

18=3 ·' 7 + l

' I ~---24·- --~

SECTION G-G

C. 12 INCH SQUARE-TO-12x24 INCH RECTANGLE

CANAL INLET AND OUTLET, TRANSITIONS CLOSED CONDUIT ROUND-TO- RECTANGULAR TftANSITIONS

FIGURE 26 REPORT HYO. 49

A. Scour after 2 hours operation. Q = 3, 1, Vp = 4. 0, canal depth = 1. OD.

Figure 27 Report Hyd 492

B. Scour after 2 hours operation. C. Scour after 1 hour operation. Vp = 4. 0 f/s, canal depth 1. 25D. Vp = 6. 0 f/s, canal depth 1. 25D.

CANAL INLET AND OUTLET TRANSITIONS

Scour Patterns- -Outlet Flows- -12- by 28-inch, Closed-conduit Transition - -Inlet Pipeline Horizontal

Left Side ,.o .. .a

.7 .. ~ .5 ..

.3

.. ·'

ro.., ...... "l'v

~ l

'

l.11 --Right Side 0 .. ---.8 1,0 1.2

Left Side ,.o • a

7 .. ~-' ..

.3

.2

Ri9ht Side o 0

A. FROM

o/v.,, •. PIPELINE UPSTREAM OUTLET TRANSITION

ii.c. -~ ~o ~. ~-'~ :.-°<I

\- ' \ •1

} Ji

--~ [.,.,~ "/

.... ~ -... ie:,.. .z .4 .& .a 1.0 1.2 1.4 1.& 1,8 2.0

'Vv .... C. OUTLET TRAVERSES

ABOVE FLOOR %

Left Side 1.0 .. ..

Left Side 1.0

Right Side

..

..

.7

..

..

.3

..

., 0

Left ·Side 1.0 .. .. .7 ..

~ .a .. .3 .. .,

--. l"'-c,

0 ••

B.

', ~ -~ ,:-_

~ .... , 0 ''111i .... ..... _

'i~ \ . -,- • \

,/ IY ,-_p .,•

-~ ........ ~ ~ ,4 .a .a 1.0 1.2 1,4 1.&

o/yAVCI.

1.8 2.0

OUTLET TRAVERSES ABOVE INVERT

- I~ ~ ...... ~

~~ ~ .... '\ ... I'..,

l, ""I\

t o• I'" ~ j

_,,I" /' ..... l,/ .,. '~ --Right Side

O O .2 .4 .& .8 1.0 1.2 1,4 1,6 1.8 2.0

-i--G . .--

v/v,., •. 0. OUTLET TRAVERSES 3°/4

ABOVE INVERT

FIGURE 28 REPORT HYD. 492

J:tH BH HI I ~ ~ u " ~ "

FROUOE NUMBER N, • o/"ia

• 7

.. ~-5 ..

• 3

' !t:lff ~¥1U~

...

E. LOSSES -vs-FROUDE NUMBER QUTLET FLOWS

Right Side

.. ·' 0 ..

0

-,_. • a 1.0

o/v.,,,. , ..

F. PIPELINE DOWNSTREAM FROM INLET TRANSITION ..,..,. _____ ..,.._ 10' conol depth

12' conol depth .,_.,. ____ A ,,·canal depth

~ ~ ~ M ~ ~ ~

FROUDE NUMBER N, • 'Y"ia G. LOSSES -vs-FROUQE NUMBER

INLET FLOWS

v, = Velocity in pipeline, fps V.• Velocity in canal, fps D = Pipeline diameter, feet

AHe • Energy loss from pipeline lo canal (outlet flows) or canal lo pipeline (inlet flows) feet, water.

CANAL INLET AND OUTLET TRANSITIONS VELOCITY DISTRIBUTIONS AND LOSS FACTORS - 12" X 28"

CLO SE D CON DUI.T TRANSITION HORIZONTAL PIPELINE

A. 0. 8 3D canal depth.

B. 1. 00D canal depth.

C. 1. 25D canal depth.

CANAL INLET AND OUTLET TRANSITION

Figure 29 Report Hyd 492

Flow From Outl~t Transition--12- by 24-inch Closed-conduit Transition 4 J/s Velocity in Pipeline, Inlet Pipe Horizontal

Figure 30 Report Hyd 492

A. Scour after 1 hour operation. Canal depth= O. 83D,

B. Scour after 1 hour operation. Canal depth = 1. 00D.

C. Scour after 1 hour operation. Canal depth = 1, 25D.

CANAL INLET AND OUTLET TRANSITIONS.

Scour Patterns--Outlet Flows--12- by 24-inch, Closed-conduit Transition 4 f/s Velocity in Pipeline. Inlet Pipe Horizontal · ·

A. 1. 00D canal depth.

B. 1. 25D canal depth.

c. Erosion after 1 hour, 1. 25D depth.

CANAL INLET AND OUTLET TRANSITIONS

Figure 31 Report Hyd 492

Flow Conditions and Scour Patterns--Outlet Flows--12- by 24-inch Transition 6 f/ s Velocity, Inlet Pipe Horizontal

Left Side 1.0 -....,,._, .. .-\. ..

. 7

.6

'-;:! .. ....

t 1 i I

.4

J .3

.2

.I

i ~

.. .-"'j Righi Side 0 .. .8 1.0 1.2

Left Side 1.0 .. .. .7

.6

o/vAVO, A. PIPELINE UPSTREAM

FROM OUTLET TRANSITION

"I!\ lo,_

:-...-; ~ -- ~ r,

D l I

,- i.\ -V

,4

j /} .. .. ,.,~ ,,l

,,,.. ~::::: ;°,.?7 _... ~ ..... ,;:r,

Right Side 0 o .2 .4 .6 .8 1,0 1.2 1.4 1.6 1.8 2.0

Yv.,vo. C. OUTLET TRAVERSES D/2

ABOVE INVERT

Left Side 1.0 .. .. • 7

.6 -~Tft#fHI ~-5

0.3 0.4 0.5 0.6 0.7 0.8

FROUDE NUMBER N, • ¾Qi E. LOSSES -vs-FROUDE NUMBER

OUTLET FLOWS Right Side

..

.. ,2

·' 0

,6

Lef I Side 1.0

..

.. ,7

.6

~ .5 .... .4

.3

.2

0

~:'lo -.,~ D,

~~~o~ ~vi.

v ~

,•"

of!lfi ....... -"" ...

\ l

.,..J l 'jI

FIGURE 32 REPOR,: H'l'D .. 492

. Righi Side 0 .2 ,4 .6 .8 1.0 1,2 1.4 1.6 1.8 2.0

Left Side 1.0 .. .8

.7

,6

~-5

Righi Side

'Oil

~

i . ~

.a 1.0

Y/yAVO,

.4

.3

.2

,I

1.2

o/vAVO. 8. OUTLP TRAVERSES °14

ABOVE INVERT

.2

~'\._ ~~--,: ~~ 0 '\ ., \7

~

1 "\ i !7 7

j~,/ /4

,,/ ~~P'i "'~

p' .4 .e .a 1.0 1.2 1.4 1.& 1.e 2.0

v/vavo. D. OUTLET TRAVERSES 3%

ABOVE INVERT

0.6

~

~ 0.5 • > :c I <I ~

~ ~ >

' 0.4

"'

~:,,.,_ ~ -"'~~ ;;;e --

o.• 0.3 0.4 0,5 0.6 0,7 Ot8

FROUDE NUMBER N, ~ ¾ija G, LOSSES -vs-,FROUDE NUMBER

INLET FLOWS

F, PIPELINE DOWNSTREAM

o----:--a 10· canal depth 12" canal depth

a---~--a 1s"canal depth

CANAL

FROM INLET TRANSITION

,#PIPELINE TRAVERSE STATION ,•-OUTLET TRAVERSE STATION

\ - ,.. ~ ,-!-- ·-~ p-------% ::o:.·>_ .. :-;._,.> rG.~-6·=··221-f

V1 "" Velocity in pipeline, fps Vz = Velocity in canal, fps D = Pipeli_ne diameter, feet

b.He = Energy loss from pipeline to canal {outlet flows) or canal to pipeline {inlet flows) feet. water.

I N L E T A N D_ 0 U T L· E T T. RANS IT IO N.S VELOCITY DISTRIBUTIONS AND LOSS FACTORS - 12"X.24"

CLOSED CONDUIT TRANSITION HORIZONTAL PIPELINE

Left Side 1. 0 ~ t-o--l.,.__,.

• . e

7

• • 4

• • '•, !~ I ~-

I\ i,

le ~, :

~!

Left Side 1.0

..

.8

.7

.. ~ .& ...

A

..

.2

0

I~ 1:::-· i-,.. I'~ "-..

'a. ~ 1.1 ... __

'"- ---· -- - r* l j,. l,

1~-~ ).P"'

I/. v~ ,___.. .. Right Side .. .8 1.0 1.2

0 Right Side 0 .. .4 .& .a 1.0 1.2 1.4 1.1 1.8 2.0

A. FROM

!fv.,.,.. PIPELINE UPSTREAM OUTLET TRANSITION

B. . . - '!Iv.... . OUTLET- TRAVERSES ' ABOVE INVERT

Left Side 1.0 .. -~ ~ i--t'""h Left Side 1.0 ..

.e

.7

1, f .e

.7

.. :::;< .&

.4

.. ·.2

~,,I ---.:,

' -

_.,.. 4

~-~

-

-~

?'_

~A i,J'

'• ~;

' -· J ;..-ti"

-.,A

(), ).)

..

.4

• 3 .. .I

'" r-.. ...., ""'- ' t'C::'

I

'"4~ - _, ~A

""'1!i,

""' i "I , .. I/ A

)~ /, L,_ ye 'J .,. -Right Side 0 o .2 .4 .& .a 1.0 1.2 1.4 1.s

'Yv-.v •• 1.8 2.0

Right Side 00 .I! .4 .8 .8 1.0 1.2 1,4 1.8 1.8 2.0

v/v~v,. C. OUTLET TRAVERSES

ABOVE INVERT % D. OUTLET TRAVERSES 30/4

ABOVE' IN-YERT

Left Side 1.0 ,-r----,c"'==!;:::::c::_-,:::r,

!~ ~C9lAH1fH 0.5 0.4 0.5 0.6 0.7 0.8

FROUOE 'NUMBER. N, a o/,rva E; LOSSES -vs-FROUOE NUMBER

OUTLET FLOWS

.• 1-+--l---l~-l--11---1

.e ........... ___,___, __ ..___,___,

. 7 l-+--1---1~-l-~-

.• l-+--1---1~-l--l+----I

;:$! .• t---+----1--1--+--M---I

. 4 l--+--1--1---1--41---1

.3 t---+----1--1--+--+---I

.2 l--+--1--1---1---1---1

.I 1--+----1--1--,-1-1-c,1-lll----l

Right Side 0 ~..,____._.__..,.__.__, .. .B I.D 1.2

o/v.,.,., F. PIPELINE DOWNSTREAM

FROM . INLET TRAN$-ITl0N

·;f_ ... :c· ., .., .

#-• "

c---_ __:.,..,._ .. -~D 10" canal depth 12• c·anal depth ------a 1s"canal depth

(PIPELINE TRAVERSE STATION

1,...~Qllll.ET TRAVE/~::~TION

.. FLOW i ctJ ,~ ;}·.·.·.::7-~-.;_._._, L --, . -- f t t:r O k- 6D ---o-lyiz"fl:l" zz" "izizz" E 0

izi" "m• .,:: ... i,;" ,ii.ii'~

a.&

a.•

0.4

.D.3 ...

G,

~ -'11... 1, ... ....... .. ....... ~ ' ~-.....

~ ...;_ tt.. II .•. . .

o.4 0.5 o.$ o. 7 o.a FROUOE .NUMBER N, a 3/Jii

* Recolculoled head loss "cQtfflcienfs for. partially filled outlet pipe.

LO.SSES -vs-FROUDE NUMBER INLET. FLOWS

V1 • Velocity in pipeline, fps V,, a Velocity In canal, fps D a Pipefine diameter, feet

AHe a Energy loss from pipeline la canal (outlet flows) or canal ta -pipelme (mlet flows) feet, water.

C A 'N.'A1 L I N L E T A N D O U T L E T T R A N'S I T I o··N $ VE'LOCIT-Y

CLOSED DISTRIBUTIONS Afl4D LOSS FA.'tlTO.RS - 12" X 24 1'' CONDUIT TRANSITION - WITH D-IVIDER PIER

HORIZONTAi: PIPELINE

I,

581

DESCRIPTION RISE

Broken-Back, 1:8 upward slope 1.000 Same trans.,with long hood to confine flow "

*Modified Warp, 1.8 upward slope " Broken-Back, 1:8 upward slope "

Broken -Back, 1:8 upward slope 0.500 Same trans., pyramid hump on floor "

*Modified Warp, 1:8 upward slope " Same trans., short hood over pipe outlet " Same trans., 12" round to 12"square pipe trans. " Same trans., 12" round to 12" square pipe trans. "

*Modified Warp, 1:8 upward slope "

Broken- Back, 1:8 upward slope 0.38 D

20° Broken-Back, 1:13.1 upward slope 0.33 D 20° Broken-Back, 1:13.1 upward slope " 20° Broken - Back, 1: 13.1 upward slope "

20° Broken-Back, 1: 13.1 upward slope " 20° Broken-Back, 1:13.1 upward slope " 20° Broken -Back, 1: 13.1 upward slope "

25°Broken--Back, I:I0.2upward slope 0.33 D 25° Broken -Back, 1: 10.2 upward slope " 25°Broken-Back, I:10.2upward slope "

25° Broken -Back, 1: 10.2 upward slope " 25° Broken -Back, 1: 10.2 upward slope " 25° Brok£Jn -Back, 1: 10.2 upward slope " 25° Brok.en -Back, 1: 10.2 upward slope "

30° Broken -Back, 1:8.3 upward slope 0.33 D 30° Broken -Back, 1:8.3 upward slope " 30° Broken -Back, 1:8.3 upward slope " 30° Broken -Back, 1: 8.3 upward slope " 30° Broken-Back, l'.8.3 upward slope " 30°Broken-Back, 1:8.3 upward slope "

B-B,I:5.5 slope,with 12"round to 12"x18i"rect. 1.00 D Same trans.,with 6i" hump on floor " Same transition, no hump "

B-B,level,with I2"round to 12"x 18j"rect. 0

Closed conduit, 12" round to I2"x 28" rect. 0.33 D Closed conduit, 12" round to 12"x 28" rect. " Closed conduit, 12" round to 12"x 28" rect. "

Closed conduit, 12" round to 12" x 24" rect. 0.33 D Closed conduit, 12" round to 12"x 24" rect. " Closed conduit, 12" round to I2"x 24" rect. " Closed conduit, with center pier " Closed conduit, with center pier "

Closed conduit,with center pier "

Closed conduit, 12"square to I2"x 24" rect. 0.33 D Closed conduit, 12"square to 12"x 24" rect. "

Closed conduit, I2"square to 12"x 24" rect. "

.,~ Warped surfaces constructed within confines of broken back transition using straight wall top and straight intersection of floor as screed guides.

SUBMERGENCE FLOW CANAL CLOSED OF OUTLET DEPTH INVERT CONDUIT

CROWN IN CANAL WIDTH SECTION

1.30 D 1.300 1.000 -" " " YES " " " -"· " " -

0.800 1.300 1.000 -" " " -" " " -" " " YES " " " YES " " " YES " " " -

0.680 1.30 D 1.000 -

0 0.67 D 1.67 D -0.17 D 0.83 D " -0.33 D 1.000 " -

0 0.67 D " -0.17 D 0.830 " -0.330 1.000 " -

0 0.670 1.670 -0.17 D 0.830 " -0.33 D 1.000 " -

-0.17 D 0.500 " -0 0.670 " -

0.17 D 0.83 D " -0.330 1.000 " -

0 0.67 D 1.67 D -0.17 D 0.83 D

. -0.33 D 1.000 " -

0 0.67 D " -0.17 D 0.830 " -0.33 D 1.00 D " -

1.300 1.300 1.000 YES " " " YES " " " YES

0.300 " " YES

-0.17 D 0.83 D 1.67 D YES 0 1.000 " YES

0.250 1.25 D " YES

-0.17 D 0.83 D 1.670 YES 0 1.00 D " YES

0.25 D 1.25 D " YES -0.17 D 0.830 " YES

0 1.000 " YES

0.25 D 1.25 D " YES

0.250 1.25 D 1.670 YES 0 1.000 " YES

-0.I7D 0.830 " YES

D = Pipeline diameter= 12"

TRANSITION PIPE LINE LENGTH

8.000 HORIZONTAL " " " " " 2: 1 SLOPE

4.000 HORIZONTAL " " " " " "

(4.0 + 1.5) D " (4.0 + 3.0) D "

4.000 2: 1 SLOPE

3.00 D 2: 1 SLOPE

4.35 D HORIZONTAL " "

" " " 2: I SLOPE " " " "

3.39 D HORIZONTAL

" " " " " 2: I SLOPE " "

" " " "

2.75 D HORIZONTAL " " " " " 2:ISLOPE " " " "

(5.5 + 2.0) D HORIZONTAL " " " 2:ISLOPE " "

6.00 D HORIZONTAL " " " "

6.000 HORIZONTAL " " " " " "

" " " "

6.00 D HORIZONTAL " " " "

INLET LOSS FACTOR

K'

----

-------0.34

-0.43 0.47 0.79t 0.65 0.66

-0.40 0.47 o.22t 0.51 0.52 0.53

-0.30 0.37 o.15t 0.62 0.55

----

0.38 0.39 0.41

0.36 0.38 0.37 0.43 0.44 0.45

0.51 0.50

0.50

OUTLET LOSS FACTOR

K

0.66 0.21 0.67

0.66

0.66 0.76 0.56 0.47 0.34 0.37 0.67

0.87t

0.59 0.61 0.75 0.62 0.63 0.67

0.44 0.49 0.65

--0.45 0.47 0.59

0.61

0.63 0.71

0.62 0.63 0.70

0.39 0.42 0.21 0.15

0.10 0.10 0.11

0,08 0.06 0.12 0.08 0.11 0.14

0.23 0.20 0.20

fl GURE 34 REPORT HYO. 492

SCOUR

EXTENSIVE EXTENSIVE EXTENSIVE MODERATE

EXTENSIVE MODERATE EXTENSIVE EXTENSIVE MODERATE MODERATE EXTENSIVE

EXTENSIVE

EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE

EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE

EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE EXTENSIVE

EXTENSIVE LIGHT

MODERATE LIGHT

MODERATE MODERATE MODERATE

MODERATE MODERATE MODERATE MODERATE MODERATE MODERATE

MODERATE MODERATE MOD.ERATE

t:.h = Vp?, - Ve2 where Vp and Ve are the 01, velocities in the pipeline and canal ,respectively 2g 2g A

t Doubtful value

K = Loss;t:.h For outlets, Loss is (hp+ vp,2g)- (he + ve~2g)

For inlets, Loss is (he+ ve~2 )-(hp+ vpt )-pipeline loss to pipe g g measuring station

CANAL INLET AND OUTLET TRANSITIONS TABLE OF OPERATING CONDITIONS AND PERFORMANCE

CHARACTERISTICS OF TRANSITIONS