Particle Image Velocimetry (PIV) Calibration PresentationA step-by-step guide to calibrating a custom

PIV system using PIVlab 1.2.

ContentsEquipmentConfigurationPhysical ProcedurePIVlab 1.2 Analysis ProcedureResultsSources of ErrorConclusionsFuture Directions

EquipmentHarvard Syringe Pump Model 33Two, plastic 60ml syringes with inside

diameter (ID)of of 26mm2m of clear rubber hose with an ID of 4.5mmT-valveClear, glass or plastic tubing with of ID of

6.25mm and outside diameter (OD) of 7.7mmBuret ClampSiliconePIV system

Configuration

Syringe Pump Procedure1. Accurately mark the glass tube at 32.6mm

(calculated with the ID using πr²h) above the opening. This is 1ml in the glass tube.

2. Silicone all tubing joints, as not to allow any air to enter or exit the tube system.

3. After silicone is cured, fill the PIV tank with water to desired level.

4. Insert the glass tube into the water, slightly under the water’s surface.

5. Using a level, plumb the glass tube to make it vertical.

Syringe Pump Procedure cont.6. Program the diameter of the syringes and

set pump to Continuous run7. Program the syringe pump to 50ml/hr.,

which calculates to 0.026m/s (which is the maximum pumping rate for these syringes)

8. Turn on PIV system9. Press “Run/Stop” on syringe pump10. Record vortex11. After experimentation, film a known

distance for a calibration image

PIVlab 1.2 Analysis Procedure: load images with sequencing style 1-2, 2-3, 3-4,…

Select region of interest (ROI) just below the glass pipe opening

Image pre-processing, enable contrast-limited adaptive histogram equalization (CLACHE) and highpass filtering (highpass) CLACHE enhances contrast in the imageHighpass sharpens the image and removes

background signals

PIV settings: set interrogation area ([px] in both dimensions) to 24 and Step ([px] spacing between the centers of interrogation area) in both dimensions to 12

Analysis: analyze all frames

Post processing: set standard deviation (stdev) filter threshhold [n*stdev] to 8. Apply to all frames

Calibration: load calibration image and select reference distance along with time step

Plot: set display parameter to velocity magnitude, smooth data to 20% and apply to all frames

A few velocity calculation options…-0- frame (represented as -0-) is the moment

the water is completely expelled from the tube into the aquarium

Velocity is calculated by programming the flow rate (i.e. .833ml/s)*distance fluid traveled (i.e. 0.0326m) = 0.026m/s² . Record the maximum velocity/frame

1. A running average: take 20 slides after -0- and average the velocity calculations (smoothing data)

2. Only look at 1 frame and average the same frame for each run

Extractions: polyline analysis A polyline is a line segment that calculates each

individual vector’s velocity. This is represented in a graph with the Y-axis as velocity and the X-axis as the distance on the line. The polyline can be drawn through the regions of highest velocity denoted by the color bar.

Set parameter to Velocity magnitude and Type to Polyline

Draw the line across the region with the highest velocity determined by the color-bar

Plot dataRecord the velocity for that frameRepeat this process to take a running average

Extractions: polyline analysis

Volume of a torus is 2π²(D/2)r².

Mass is calculated using the density of H2O at room temp.

Smooth the data to 100%.

Torus volume

Torus picture courtesy of: http://blog.teachersource.com/2012/01/

Measure distance and angle: measure radius (D/2) from core to core

To insure accurate measurement of radius r, take 6 measurements from the same side of the torus half from the core to the outside wall and average them: radius 1

Radius 2…

Radius 3… repeat 3 more times

Results 

Results cont.

Run

1ml High Velocity (0.026m/s)

1ml Low Velocity (0.016m/s)

1ml High Velocity Torus Volume (ml)

1ml Low Velocity Torus Volume (ml)

High Velocity Acceleration (m/s²)

High Velocity Force (N)

High Velocity Work (J)

Low Velocity Acceleration (m/s²)

Low Velocity Force (N)

Low Velocity Work (J)

1 0.027 0.015 1.029 0.978 5.21 0.00534 3.20E-05 3.25 0.00316 1.90E-05

2 0.026 0.021 0.986 1.015 5.22 0.00513 3.07E-05 3.24 0.00327 1.96E-05

3 0.020 0.023 0.995 1.021 5.24 0.00520 3.12E-05 3.25 0.00330 1.98E-05

4 0.027 0.019 1.028 1.023 5.22 0.00535 3.21E-05 3.26 0.00332 1.99E-05

5 0.025 0.017 1.040 0.998 5.23 0.00542 3.25E-05 3.25 0.00323 1.94E-05

Ave. 0.025 0.019 1.016 1.001

SE 0.0011 0.0013 0.0105 0.0085

t -0.434 2.549 1.519 0.861

p <0.05 <0.05 <0.05 <0.05

Ave. Accel. (m/s²) 5.22 3.25Ave. Force (N) 0.00529 0.00326Ave.Work (J) 3.17E-05 1.95-05

Possible Sources of ErrorThe Harvard Apparatus Twin Syringe Pump

Model 33 has an accuracy within ±0.35% and reproducibility within ±0.1%

The clear rubber hose may be expanding and contracting due to thermal fluctuations

Convection currents with the experimental system

ConclusionsAll measurements using this 2D PIV system

are not statistically different from the expected values suggested by the syringe pump apparatus

Although the Reynolds number (Re) for the syringe pump experiment is 162 and 100 for 0.026m/s and 0.016m/s, respectively, and the Re estimate for aquatic leaping in Rana catesbeiana is 16100, this method can be used to calculate force, work, and power of amphibian propulsion in an aquatic medium

Future DirectionsTo use a static glass tube from the syringes to

keep the water pressure constantTo use larger syringes with a faster syringe

pump will allow vortices to be produced at higher Re ranges, possibly within the frog aquatic leap velocities

To produce a wider range of flow velocitiesConduct experiment in a more temperature

stable area

Acknowledgements Undergraduate Students Duane Barbano Erik Dillingham Antonia Tallante Nicholas Gengler Russell Nelson Maxwell Wheeler

Graduate Students Krysta Powers, M.S. student Sang Hoon Yeo, Ph.D. student Kari Taylor, M.S. student

Post-docs Cinnamon Pace, Ph. D. Jenna Monroy, Ph.D.

FacultyKiisa Nishikawa, Physiology, NAUStan Lindtsted, Physiology, NAUAlice Gibb, Physiology, NAUTed Uyeno, Biomechanics, VSUBrent Nelson, Mechanical Engineering, NAUDavid Lee, Biomechanics, UNLV

FundingNAU VPRNAU GSGSigma Xi GIAR Grant G20111015158992

PersonalMr. Pippiens