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Transcript of Ana L. Quaresma PhD Student, IST [email protected] António N. Pinheiro Full Professor,...
Ana L. QuaresmaPhD Student, IST
António N. PinheiroFull Professor, IST
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Introduction
Rivers are becoming increasingly fragmented with their longitudinal
connectivity compromised by man-made obstacles such as dams which
affect fish movements leading to populations decrease and genetic
deterioration. Fishways re-establish this connectivity allowing for fish
migration.
Penide hydroelectric plant pool fishway (Santo, 2005)
Cross-walls with notches and bottom orifices (Santo, 2005)
In Portugal, the most common fish pass is the pool-type one (Santos et
al., 2006).
It consists of a series of pools, arranged in a stepped pattern, separated
by cross-walls that can be equipped with vertical slots, submerged
orifices and surface notches.
1
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Framework
In recent years, intense experimental work
studying the behaviour of cyprinid species was
done in an indoor full scale pool-type fishway, 10
m long, 1 m wide and 1.2 m high of adjustable
slope, located in LNEC (Portuguese National
Laboratory of Civil Engineering) LNEC’s prototype pool-type fishway facility
IST’s 1:2.5 scaled pool-type fishway facility
A 1:2.5 scaled fishway of the existing at LNEC, equipped with
a recirculation hydraulic circuit was built at IST (Technical
Superior Institute), to make pool-type fishway hydraulic
studies easier and allow performing a larger number of
experiments in a shorter period of time.
2
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Physical Model
3
IST’s 1:2.5 scaled pool-type fishway facility
Cross-walls detail: consecutive orifices positioned in opposite
sides of the cross-walls
IST’s 1:2.5 scaled fishway is 5.7 m long, 0.4 m wide and 0.5 m high of
adjustable slope.
It consists of adjustable pools (now 4 pools 0.76 m long x 0.40 m
wide x 0.50 m high) divided by five cross-walls equipped with bottom
orifices (0.8 x 0.8 m). Consecutive orifices were positioned on
opposite sides of the cross-walls, creating a sinusoidal flow path.
IST’s experimental fishway facility: elevation
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Objectives
4
The fishway located at IST is used to calibrate numerical
simulations with hydraulic measurements using ADV (Acoustic
Doppler Velocimeter) and PIV (Particle Image Velocimeter)
equipment to measure velocitiesIST’s 1:2.5 scaled pool-type fishway
facility
Velocity magnitude calculation using FLOW-3D
Our goal is to develop innovative design solutions with different
geometries using FLOW-3D CFD modelling (varying slopes, basins,
slots, orifices and notches dimensions).
To determine the configurations that better suit species capabilities to
progress upstream parameters like turbulence, Reynolds shear stress
and kinetic energy will be correlated with fish behaviour.
The chosen configurations will be tested with fishes at LNEC’s facility
to verify their efficiency. LNEC’s prototype pool-type fishway
facility
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
x
z
Numerical Model - Geometry
5
Bed Bed, cross-walls and walls detail
1. Bed
2. Cross-walls
3. Walls
4. Auxiliary solids
Auxiliary solids detail
Geometry 1
7 flux surface baffles:
1 flux surface baffle upstream, 5 at the cross-walls and one dowstream
Initial conditions:
Hydrostatic pressure, with gravity g = -9.8 m/s2 in z direction
Initial fluid elevation = 1 m (dowstream water surface elevation)
Rendered bed and cross-walls (0.03 m cells)
4 components:
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Numerical Model - Meshing
6
Specified pressure in X Min and X Max
Simmetry in Z Min and Z Max and
Wall in Y Min and Y Max
Cubic cells
Mesh block planes at cross-walls, walls
and orifices (12 in x and z direction and 6
in y direction)
Mesh block boundaries
Mesh block planes detail
Mesh block details
Geometry 1
1 mesh block
Boundaries
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
1. Bed
2. Cross-walls
3. Walls
4. Auxiliary solids
Numerical Model - Geometry
7
1 flux surface baffle upstream at the entrance of the flume, 1 at the beginning of the horizontal bed,
5 at the cross-walls and one downstream
Hydrostatic pressure, with gravity gx = 0.831 m/s2 in x direction and gz = -9.775 m/s2 in z direction
Initial fluid elevation = 1.587 m (downstream water surface elevation)
x
z
Rotated bed
Initial bed
Rotated geometry detail
Rendered bed and cross-walls (containing block: 0.02 m cells and nested blocks: 0.01 m cells)
Geometry 2
4 components rotated to make fishway bed paralel to x direction:
8 flux surface baffles:
Initial conditions:
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Numerical Model - Meshing
8
Geometry 2
Containing block
Specified pressure in X Min and X Max
Simmetry in Z Min and Z Max and
Wall in Y Min and Y Max
Nested blocks
Simmetry in all boundaries
Cubic cells
The containing block cell size is multiple of
the nested block cell size, 2:1 and has mesh
planes at all six edges of the nested block
Mesh block boundaries
Mesh block planes detail
Mesh block detail
6 mesh blocks, 5 nested blocks at cross-walls
Boundaries:
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Model setup
Volume-of-fluid advection:
Default VOF and Split Lagrangian Method
Momentum advection:
First order and Second order monotonicity preserving
Geometry 1 - Gravity g = -9.81 m/s2 in z direction
Geometry 2 - Gravity gx = 0.831 m/s2 in x direction and gz = -9.775 m/s2 in z direction
Viscosity and turbulence: Renormalized group model (RNG)
No-slip
9
Physics:
Numerics:
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Calibration - Approach to steady state
10
Approach to Steady State - Geometry 1(Default VOF; RNG model; Dynamically computed TLEN)
3.5
4.0
4.5
5.0
5.5
6.0
6.5
0 40 80 120 160 200 240 280 320 360Time (s)
Q (
l/s)
Minimum Q Flowmeter Average Q Flowmeter
Maximum Q Flowmeter
Average Q - 0.03 Cells; 2nd order monotonicity preserving Average Q - 0.03 Cells; 1st order
Average Q - 0.02 Cells; 2nd order monotonicity preserving Average Q - 0.02 Cells; 1st order
Average Q - 0.01 Cells Restart; 2nd order monotonicity preserving Average Q - 0.01 Cells Restart; 1st order
33.8%
24.7%
30.1%
21.7%
13.3 %
18.2%
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
3.5
4.0
4.5
5.0
5.5
6.0
6.5
0 40 80 120 160 200 240 280 320 360
Q (
l/s)
Time (s)
Approach to Steady State - Geometry 1 vs Geometry 2(Default VOF; RNG model; Dynamically computed TLEN)
Minimum Q Flowmeter Average Q Flowmeter
Maximum Q Flowmeter
Average Q - 0.03 Cells; 2nd order mon. pres. - Geom. 1 Average Q - 0.03 Cells; 1st order - Geom. 1
Average Q - 0.02 Cells; 2nd order mon. pres. - Geom. 1 Average Q - 0.02 Cells; 1st order - Geom. 1
Average Q - 0.01 Cells Restart; 2nd order mon. pres. - Geom. 1 Average Q - 0.01 Cells Restart; 1st order - Geom. 1
Avg Q - 0.02 Cells; 0.01 Cells at crosswalls; 2nd order m. p. - Geom. 2 Avg Q - 0.02 Cells; 0.01 Cells at crosswalls; 1st order - Geom. 2
Avg Q - 0.01 Cells; 0.005 Cells at crosswalls; 2nd order m. p. - Geom. 2 Avg Q - 0.01 Cells; 0.005 Cells at crosswalls; 1st order - Geom. 2
33.8%
24.7%
30.1%
21.7%
13.3 %
18.2%
7.6%4.7%11.8%
17.4%
Calibration - Approach to steady state
11
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Calibration - Surface Elevation
12
Surface Elevation - Geometry 1(Default VOF; RNG model; Dynamically computed TLEN)
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0Length along flume (m)
Su
rfac
e el
evat
ion
(m
)
Surface Elevation (Physical Model)0.03 Cells; 2nd order monotonicity preserving0.03 Cells; 1st order0.02 Cells; 2nd order monotonicity preserving0.02 Cells; 1st order0.01 Cells Restart; 2nd order monotonicity preserving0.01 Cells Restart; 1st order
Maximum Difference
2.8%3.0%3.1%1.9%5.2%3.8%
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Calibration - Surface Elevation
13
Surface Elevation - Geometry 1(Default VOF; RNG model; Dynamically computed TLEN)
1.110
1.115
1.120
1.125
1.130
1.135
1.140
1.145
1.150
1.155
1.160
1.165
1.170
1.175
1.180
1.185
1.190
1.195
1.200
3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0Length along flume (m)
Su
rfac
e el
evat
ion
(m
)
Surface Elevation (Physical Model)0.03 Cells; 2nd order monotonicity preserving0.03 Cells; 1st order0.02 Cells; 2nd order monotonicity preserving0.02 Cells; 1st order0.01 Cells Restart; 2nd order monotonicity preserving0.01 Cells Restart; 1st order
1.7%0.7%1.7%1.2%3.7%2.2%
Maximum Difference
3rd pool detail
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Su
rfac
e el
evat
ion
(m
)
Length along flume (m)
Surface Elevation - Geometry 1 vs Geometry 2(Default VOF; RNG model; Dynamically computed TLEN)
Surface Elevation (Physical Model)0.02 Cells; 2nd order monotonicity preserving - Geom. 10.02 Cells; 1st order - Geom. 10.01 Cells; 2nd order monotonicity preserving - Geom. 10.01 Cells; 1st order - Geom. 10.02 Cells; 0.01 Cells at crosswalls; 2nd order m.p. - Geom. 20.02 Cells; 0.01 Cells at crosswalls; 1st order - Geom. 20.01 Cells; 0.005 Cells at crosswalls; 2nd order m.p. - Geom. 20.01 Cells; 0.005 Cells at crosswalls; 1st order - Geom. 2
Maximum Difference
3.1%1.4%5.2%3.8%3.0%5.1%2.8%2.8%
Calibration - Surface Elevation
14
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
1.110
1.115
1.120
1.125
1.130
1.135
1.140
1.145
1.150
1.155
1.160
1.165
1.170
1.175
1.180
1.185
1.190
1.195
1.200
3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0
Su
rfac
e el
evat
ion
(m
)
Length along flume (m)
Surface Elevation - Geometry 1 vs Geometry 2(Default VOF; RNG model; Dynamically computed TLEN)
Surface Elevation (Physical Model)0.02 Cells; 2nd order monotonicity preserving - Geom. 10.02 Cells; 1st order - Geom. 10.01 Cells; 2nd order monotonicity preserving - Geom. 10.01 Cells; 1st order - Geom. 10.02 Cells; 0.01 Cells at crosswalls; 2nd order m.p. - Geom. 20.02 Cells; 0.01 Cells at crosswalls; 1st order - Geom. 20.01 Cells; 0.005 Cells at crosswalls; 2nd order m.p. - Geom. 20.01 Cells; 0.005 Cells at crosswalls; 1st order - Geom. 2
Maximum Difference
1.7%1.2%3.7%2.2%2.8%2.1%2.1%1.1%
3rd pool detail
Calibration - Surface Elevation
15
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Calibration - VOF Method
16
Approach to Steady State - VOF Method(2nd order monotonicity preserving momentum advection; RNG model; Dynamically computed TLEN)
3.5
4.0
4.5
5.0
5.5
6.0
6.5
0 40 80 120 160 200 240 280 320 360Time (s)
Q (
l/s)
Minimum Q Flowmeter Average Q Flowmeter
Maximum Q Flowmeter
Avg Q - 0.03 Cells; Default VOF - Geom. 1 Avg Q - 0.03 Cells; Split Lagrangian Method - Geom. 1
Avg Q - 0.02 Cells; 0.01 Cells at crosswalls; Default VOF - Geom. 2 Avg Q - 0.02 Cells; 0.01 Cells at crosswalls; Split Lagrangian M - Geom. 2
33.8% 32.7%
8.4% 7.6%
Computation time for 100 s of simulation (h)
Geometry 1 – Default VOF 0.54
Geometry 1 – Split Lagrangian Method 0.55
Geometry 2 – Default VOF 14.0
Geometry 2 – Split Lagrangian Method 14.9
Intel(R) Core(TM) i7 CPU [email protected] GHz, 6.0GB RAM
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Calibration - VOF Method
17
Surface Elevation - VOF Method(2nd order monotonicity preserving; RNG model; Dynamically computed TLEN)
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0Length along flume (m)
Su
rfac
e el
evat
ion
(m
)
Surface Elevation (Physical Model)
0.03 Cells; Default VOF - Geom. 1
0.03 Cells; Split Lagrangian Method - Geom. 1
0.02 Cells; 0.01 Cells at crosswalls; Default VOF - Geom. 2
0.02 Cells; 0.01 Cells at crosswalls; Split Lagrangian M. - Geom. 2
Maximum Difference
2.8%2.8%3.0%3.1%
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035
Ave
rag
e Q
(l/
s)
Cubic cell size (m)
Mesh dependency study: smooth walls(Default VOF; RNG model; Dynamically computed TLEN)
Min Q Flowmeter Avg Q Flowmeter Max Q Flowmeter
2nd order monotonicity preserving - Geom. 1 1st order - Geom.1 2nd order monotonicity preserving - Geom. 2
1st order - Geom.2
2.8%
10.1%2.4%
7.4%
18.2%
13.3%
6.4%
4.7%
8.3%
7.6%
Calibration - Mesh Dependency study
18
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Calibration - TLEN
19
Flow rate as a function of Max. Turb. Mix Length (Geom. 1 - 0.03 Cells; Default VOF; RNG model
Geom. 2 - 0.02 cells; 0.01 cells at crosswalls; Default VOF; RNG model)
4.20
4.40
4.60
4.80
5.00
5.20
5.40
5.60
5.80
6.00
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40Maximum Turbulent Mixing Length TLEN (m)
Flo
w r
ate
(l/s
)
Maximum Q Flowmeter Average Q FlowmeterMinimum Q FlowmeterDynamically Computed TLEN; 2nd order m. p. - Geom. 1 Specified TLEN; 2nd order m. p. - Geom. 1Dynamically computed TLEN; 1st order; Geom. 1 Specified TLEN; 1st order - Geom. 1Dynamically computed TLEN; 2nd order m. p. - Geom. 2 Specified TLEN; 2nd order m. p.; Geom. 2Dynamically Computed TLEN; 1st order - Geom. 2 Specified TLEN; 1st order - Geom. 2
31.6%
1.7%
1.1% 3.5%
24.0%
0.6%
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Surface Elevation(Geom. 1 - 0.03 Cells; 2nd order monotonicity preserving momentum advection; Default VOF; RNG model Geom. 2 - 0.02 cells; 0.01 cells at crosswalls; 1st order momentum advection; Default VOF; RNG model)
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6Length along flume (m)
Su
rfac
e el
evat
ion
(m
)
Surface elevation (Physical Model)
TLEN = 0.10 - Geom. 1
TLEN = 0.10; ks = 0.00003048 m (glass min) - Geom. 1
TLEN = 0.10; ks = 0.0009144 m (glass max) - Geom. 1
TLEN = 0.10; ks = 0.03048 m (concrete max) - Geom. 1
TLEN = 0.10; ks = 4.267E-7 m (hyd.smooth) - Geom. 1
TLEN = 0.10 - Geom. 2
TLEN = 0.10; ks = 0.00003048 (glass min) - Geom. 2
TLEN = 0.10; ks = 0.0009144 m (glass max) - Geom. 2
Maximum Difference
3.0%1.8% (0.08%)3.0% (0.4%3.0% (0.8%)3.0% (0.1%)3.4%5.1% (4.7%)3.3% (0.3%)
Calibration – Roughness study
20
ks = 0.00003048 m (glass min) increases Flow rate Q 0.04% (Geom. 1) and 0.7 % (Geom. 2)
ks = 0.0009144 m (glass max) decreases Flow rate Q 0.36% (Geom. 1) and increases Q 0.9 % (Geom. 2)
ks = 0.03048 m (concrete max) decreases Flow rate Q 1.11%
ks = 4.267 x 10-7 m (hyd. smooth) increases Flow rate Q 0.08%
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Surface Elevation(Geom. 1 - 0.03 Cells; 2nd order monotonicity preserving momentum advection; Default VOF; RNG model Geom. 2 - 0.02 cells; 0.01 cells at crosswalls; 1st order momentum advection; Default VOF; RNG model)
1.100
1.105
1.110
1.115
1.120
1.125
1.130
1.135
1.140
1.145
1.150
1.155
1.160
3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4Length along flume (m)
Su
rfa
ce e
leva
tio
n (
m)
Surface elevation (Physical Model)
TLEN = 0.10 - Geom. 1
TLEN = 0.10; ks = 0.00003048 m (glass min) - Geom. 1
TLEN = 0.10; ks = 0.0009144 m (glass max) - Geom. 1
TLEN = 0.10; ks = 0.03048 m (concrete max) - Geom. 1
TLEN = 0.10; ks = 4.267E-7 m (hyd.smooth) - Geom. 1
TLEN = 0.10 - Geom. 2
TLEN = 0.10; ks = 0.00003048 (glass min) - Geom. 2
TLEN = 0.10; ks = 0.0009144 m (glass max) - Geom. 2
Maximum Difference
1.1%1.1% (0.03%)0.8% (0.4%1.0% (0.6%)1.1% (0.09%)3.4%3.0% (0.4%)3.3% (0.2%)
3rd pool detail
Calibration – Roughness study
21
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Calibration – Computation Time
22
Computation time for 100 s of
simulation (h)
Total number of cells (active and passive)
Total number of active cells
0.03 cells; 2nd order monotonicity preserving (a) 0.54 115 835 46 803
0.03 cells; 1st order (a) 0.49 115 835 46 803
0.02 cells; 2nd order monotonicity preserving (a) 2.1 340 755 140 110
0.02 cells; 1st order (b) 1.9 340 755 140 110
0.01 cells Restart; 2nd order monotonicity preserv. (a) 42.7 2 428 805 1 027 913
0.01 cells Restart; 1st order (a) 26.1 2 428 805 1 027 913
0.02 cells; 0.01 cells at crosswalls; 2nd order mon. p. (a) 14.0 331 230 213 009
0.02 cells; 0.01 cells at crosswalls; 1st order (a) 11.5 331 230 213 009
0.01 cells; 0.005 cells at crosswalls; Rest.; 2nd o. m. p. (c) 119.5 ( ≈ 5 days) 2 279 774 1 464 192
0.01 cells; 0.005 cells at crosswalls; Restart; 1st order (c) 40.2 2 279 774 1 464 192
(a) Intel(R) Core(TM) i7 CPU [email protected] GHz, 6.0GB RAM(b) Intel Core2 Quad CPU [email protected] GHz, 3.0GB RAM
(c) Intel(R) Core(TM) i7-3770 [email protected] GHz, 32.0GB RAM
Ge
om
etr
y 1
Geo
met
ry 2
(r
ota
ted
)
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Calibration – Final Results
23
Renormalized group model (RNG); Default VOF method; 1st order momentum advection; TLEN = 0.10
ks = 0.0009144 m (glass max)
Flowrate Q – Average Q = 4.98 l/s Physical Model Average Q = 4.44 l/s Dif. = 12.3%
Free surface elevation – Largest Dif. = 0.012 m Dif. = 3.4%
Computation time for 100 s of simulation time (h) – 21.8 h
Geometry 1:
Renormalized group model (RNG); Default VOF method; 1st order momentum advection; TLEN = 0.10
Flowrate Q – Average Q = 4.60 l/s Physical Model Average Q = 4.44 l/s Dif. = 3.5%
Free surface elevation – Largest Dif. = 0.013 m Dif. = 3.4%
Computation time for 100 s of simulation time (h) – 11.8 h
Geometry 2:
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Surface Elevation
1.10
1.11
1.12
1.13
1.14
1.15
1.16
1.17
1.18
1.19
1.20
3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0Length along flume (m)
Su
rfac
e el
evat
ion
(m
)
Physical Model vs Numerical Model
24
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Physical Model vs Numerical Model
Flowrate Q – Average Q = 4.60 l/s Physical Model Average Q = 4.44 l/s Dif. = 3.5%
25
Surface Elevation(Geom. 2 - 0.02 cells; 0.01 cells at crosswalls; 1st order momentum advection; Default VOF; RNG model; TLEN = 0.10)
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
Length along flume (m)
Su
rfac
e el
evat
ion
(m
)
Surface elevation (Physical Model)
Surface elevation (Numerical Model) Maximum Difference = 3.4%
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Surface Elevation(Geom. 2 - 0.02 cells; 0.01 cells at crosswalls; 1st order momentum advection; Default VOF; RNG model)
1.10
1.11
1.12
1.13
1.14
1.15
1.16
1.17
1.18
1.19
1.20
3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4Length along flume (m)
Su
rfac
e el
evat
ion
(m
)
Surface elevation (Physical Model)
Surface elevation (Numerical Model)
3rd pool detail
Maximum Difference = 3.4%
Physical Model vs Numerical Model
26
Flowrate Q – Average Q = 4.60 l/s Physical Model Average Q = 4.44 l/s Dif. = 3.5%
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Numerical Model – Velocity Magnitude
27
Z = 0.04 m above bottom(orifice axis)
Velocity magnitude (m/s)
Z = 0.088 m above bottom(25% hm)
Z = 0.176 m above bottom(50% hm)
Z = 0.282 m above bottom(80% hm)
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Physical Model vs Numerical Model Velocity Magnitude
28
3rd Pool
Z (X,Y) VPhysical model (m/s) VFlow 3D (m/s) Dif. (%)
4 cm above bottom
(orifice axis)
(4, 4) 1.08 0.83 22.8
(4,36) 0.11 0.10 9.9
(12,4) 0.82 0.82 0.7
(28,36) 0.14 0.16 11.6
17.6 cm above bottom
(50% hm)
(4,4) 0.10 0.06 39.7
(28,36) 0.30 0.24 19.2
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Numerical Model – Turbulent Energy
29
Z = 0.04 m above bottom(orifice axis)
Turbulent Energy (J/kg)
Z = 0.088 m above bottom(25% hm)
Z = 0.176 m above bottom(50% hm)
Z = 0.282 m above bottom(80% hm)
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Conclusions
• It is very important to calibrate and validate a model
In the present case study:
– Significant changes in results depending on:
• Cell size
• Momentum advection method
– Some changes dependig on:
• Specified TLEN instead of Dynamically computed TLEN
– Neglectible changes depending on:
• VOF Method
• Surface roughness
• Still work to do but promising results
• Reynolds shear stress as an additional output variable would be a good followup
30
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Ana Quaresma; António Pinheiro
Acknowledgements
The authors thank Raúl Martín from Simulaciones y proyectos, SL for his suggestions.
Ana Quaresma was supported by a grant from UTL (Technical University of Lisbon in the beginning of the work and afterwards by a grant (SFRH/BD/87843/2012) from FCT (Science and Technology Foundation).
References
• FLOW-3D. Advanced Hydraulics Training, 2012. 12th FLOW-3D European Users Conference.
• Santo, M. (2005), Dispositivos de passagem para peixes em Portugal. DGRF, Lisboa.
• Santos, J.M., Ferreira, M.T., Pinheiro, A.N., Bochechas, J., 2006. Effects of small hydropower plants on
fish assemblages in medium-sized streams in Central and Northern Portugal. Aquatic Conservation, 16:
373–388.
Ana L. [email protected]
António N. [email protected]
Numerical modelling of flows in pool-type fishways equipped with bottom orifices
Questions?Comments?