Work Description

Velocity and Vorticity Data Collected by and used to Validate a Field PIV System

Dataset to accompany "Low-cost field particle image velocimetry for quantifying environmental turbulence"

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By Jones, Kaylin and Cotel, Aline J.
Contact: kaylinj@umich.edu
17 May 2023

Jones, K. and Cotel, A.J. 2023. Low-cost field particle image velocimetry for quantifying environmental turbulence. Journal of Ecohydraulics. Currently in review.

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Research Overview
Detailed environmental turbulence measurements are lacking, largely due to inadequate available field instrumentation. This research presents a new design for an instrument intended to provide these measurements, a rugged, low-cost instrument that utilizes particle image velocimetry (PIV) to measure environmental flows. Testing of the instrument was performed both in the laboratory and field, and consisted of both validation and proof-of-concept testing. Data collection and analysis was performed over the course of 10 July 2021 - 1 September 2022. This research was funded by a Rackham Graduate Student Research Grant awarded to Kaylin Jones.

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Methods
Data collection: laboratory testing
To validate the system's ability to measure average velocity of a flow and turbulent kinetic energy (TKE) of a flow, the PIV system, an acoustic doppler velocimeter (ADV), and an electromagnetic flowmeter (EM) were all used to measure a variety of flows. Uniform flow at six different velocities were measured using each method to validate the system's average velocity measurements. Flow behind a cylinder at two different velocities was measured using both the PIV and ADV to validate the system's ability to accurately measure TKE. Vorticity in the flow behind the cylinder was also qualitatively explored using only the novel PIV as a form of proof-of-concept, as this measurement was unable to be repeated by either of the other instruments.

Data collection: field testing
The novel PIV was deployed at three different field sites in the Huron River in Ann Arbor, MI from July - October 2021 for further validation and proof-of-concept. Field site 1 was a bulrush patch that had previous measurements, and was used to validate the novel PIV in the field. Field site 2 was an area of recirculation in Bandemer Park, and here three different locations all within close proximity of one another but with different turbulence signatures were recorded as proof-of-concept for the instrument. Field site 3 was a boulder in Island Park periodically shedding eddies, and the difference in flow when an eddy was being shed vs when it was not being shed was used as an additional proof-of-concept dataset.

Data analysis
All data was analyzed using PIVlab, a Matlab-based PIV analysis software. This software generated .txt files for various characteristics at many points in the flow, which were combined into Excel files and interpolated between the discrete points to map the entire flow. The flow characteristics generated were u-velocity, v-velocity, vorticity, and velocity magnitude. The combined Excel files for all laboratory and field testing, and the various Matlab codes used in data compilation, are contained in this dataset.

Link to PIVlab: https://www.mathworks.com/matlabcentral/fileexchange/27659-pivlab-particle-image-velocimetry-piv-tool-with-gui#:~:text=PIVlab%20is%20a%20GUI%20based,parameters%20of%20the%20flow%20pattern.

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Glossary of terms in dataset

PIV -- particle image velocimetry
ADV -- acoustic doppler velocimeter
EM -- electromagnetic flowmeter
Marsh McBirney -- type of EM
TKE -- turbulent kinetic energy
bulrush patch -- reference to Field Site 1
bandemer -- reference to Field Site 2
boulder -- reference to Field Site 3
x coord -- x-coordinate of data point
y coord -- y-coordinate of data point

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File Inventory

Lab validation files
"labvalidation_velocityaverages.xlsx" -- average velocities found in laboratory validation from PIV, ADV, and EM during uniform flow trials
"labvalidation_ADV_6Hzvelocities.xlsx" -- velocity measurements from ADV used in TKE calculation for 6 Hz flow around cylinder
"labvalidation_ADV_10Hzvelocities.xlsx" -- velocity measurements from ADV used in TKE calculation for 10 Hz flow around cylinder
"labvalidation_10Hz_vorticity.xlsx" -- vorticity measurements from PIV for 10 Hz flow around cylinder
"labvalidation_10Hz_cylindervelocities.xlsxl" -- velocity measurements from PIV for 10 Hz flow around cylinder used in TKE calculation. Contains 2 sheets, one for u-velocity components, one for v-velocity components
"labvalidation_6Hz_vorticity.xlsx" -- vorticity measurements from PIV for 6 Hz flow around cylinder
"labvalidation_6Hz_cylindervelocities.xlsx" -- velocity measurements from PIV for 6 Hz flow around cylinder used in TKE calculation. Contains 2 sheets, one for u-velocity components and one for v-velocity components

Field site 1 files
"bulrushpatch_vvelocity.xlsx" -- v-velocity component from PIV measurements at field site 1
"bulrushpatch_vorticity.xlsx" -- vorticity from PIV measurements at field site 1
"bulrushpatch_velocitymagnitude.xlsx" -- velocity magnitude from PIV measurements at field site 1
"bulrushpatch_uvelocity.xlsx" -- u-velocity component from PIV measurements at field site 1

Field site 2 files *Note field site 2 contains measurements at 3 sub-sites, termed Location A, Location B, and Location C
Location A files
"bandemer_locationA_uvelocity.xlsx" -- u-velocity component from PIV measurements at field site 2 location A
"bandemer_locationA_velocitymagnitue.xlsx" -- velocity magnitude from PIV measurements at field site 2 location A
"bandemer_locationA_vorticity.xlsx" -- vorticity from PIV measurements at field site 2 location A
"bandemer_locationA_vvelocity.xlsx" -- v-velocity components from PIV measurements at field site 2 location A

Location B files
"bandemer_locationB_uvelocity.xlsx" -- u-velocity component from PIV measurements at field site 2 location B
"bandemer_locationB_velocitymagnitude.xlsx" -- velocity magnitude from PIV measurements at field site 2 location B
"bandemer_locationB_vorticity.xlsx" -- vorticity from PIV measurements at field site 2 location B
"bandemer_locationB_vvelocity.xlsx" -- v-velocity compoenent from PIV measurements at field site 2 location B

Location C files
"bandemer_locationC_uvelocity.xlsx" -- u-velocity component from PIV measurements at field site 2 location C
"bandemer_locationC_velocitymagnitude.xlsx" -- velocity magnitude from PIV measurements at field site 2 location C
"bandemer_locationC_vorticity.xlsx" -- vorticity from PIV measurements at field site 2 location C
"bandemer_locationC_vvelocity.xlsx" -- v-velocity component from PIV measurements at field site 2 location C

Field site 3 files *Note field site 3 contains two sub-datasets, termed Background flow and FEP (flow with eddies present)
Background flow files
"boulder_background_uvelocity.xlsx" -- u-velocity components from PIV measurements at field site 3 for background flow
"boulder_background_velocitymagnitude.xlsx" -- velocity magnitude from PIV measurements at field site 3 for background flow
"boulder_background_vorticity.xlsx" -- vorticity from PIV measurements at field site 3 for background flow
"boulder_background_vvelocity.xlsx" -- v-velocity component from PIV measurements at field site 3 for background flow

FEP files
"boulder_FEP_uvelocity.xlsx" -- u-velocity component from PIV measurements at field site 3 for FEP
"boulder_FEP_velocitymagnitude.xlsx" -- velocity magnitude from PIV measurements at field site 3 for FEP
"boulder_FEP_vorticity.xlsx" -- vorticity from PIV measurements at field site 3 for FEP
"boulder_FEP_vvelocity.xlsx" -- v-velocity components from PIV measurements at field site 3 for FEP

Codes used in analysis
"compile_uvel.m" -- Matlab code used to compile individual u-velocity component data .txt files into a single .csv file
"compile_vvel.m" -- Matlab code used to compile individual v-velocity component data .txt files into a single .csv file
"compile_vorticity.m" -- Matlab code used to compile individual vorticity data .txt files into a single .csv file
"compile_velocitymagnitude.m" -- Matlab code used to compile individual velocity magnitude data .txt files into a single .csv file