This readme.txt file was generated on <2020-10-07> by the Data Repository for the University of Minnesota (DRUM) Recommended citation for the data: Kang, Peter K. (2020). Particle image velocimetry data characterizing flow and turbulence fields at free-flow-porous media interface. Retrieved from the Data Repository for the University of Minnesota, https://doi.org/10.13020/qe5z-sj53. ------------------- GENERAL INFORMATION ------------------- 1. Title of Dataset: Particle image velocimetry data characterizing flow and turbulence fields at free-flow-porous media interface 2. Author Information Principal Investigator Contact Information Name: Peter K Kang Institution: University of Minnesota Address: Email: pkkang@umn.edu ORCID: Associate or Co-investigator Contact Information Name: Junsong Kim Institution: University of Minnesota Address: Email: ORCID: 3. Date of data collection: 2019-11-26 to 2019-11-30 4. Geographic location of data collection (where was data collected?): 5. Information about funding sources that supported the collection of the data: -------------------------- SHARING/ACCESS INFORMATION -------------------------- 1. Licenses/restrictions placed on the data: CC0 1.0 Universal (http://creativecommons.org/publicdomain/zero/1.0/) 2. Links to publications that cite or use the data: 3. Links/relationships to ancillary data sets: 4. Was data derived from another source? If yes, list source(s): -------------------------- METHODOLOGICAL INFORMATION -------------------------- 1. Description of methods used for collection/generation of data: The data includes two-dimensional (2D) instantaneous velocity fields and time-averaged 2D flow properties. We obtained the velocity data in an experimental flume, which is composed of an open channel and underlying porous media, at the St. Anthony Falls Laboratory, University of Minnesota using Particle Image Velocimetry (PIV). The PIV is a non-intrusive laser optical measurement technique, which measures flow at the high spatiotemporal resolution by estimating cross-correlations between laser-illuminated subsequent images recorded by a high-speed camera. We used the PIV-measured 2D flow fields to validate the results of numerical flow simulations based on Large Eddy Simulation. The main objective of this study is to investigate pore-scale flow effects on solute transport across open channel- porous media interfaces. The released data would also be useful to researchers who need to validate flow simulation results. 2. Methods for processing the data: We post-processed the recorded images using the open- source PIV software, PIVlab (Thielicke and Stamhuis, 2014) 3. Instrument- or software-specific information needed to interpret the data: 5. Environmental/experimental conditions: 6. Describe any quality-assurance procedures performed on the data: 7. People involved with sample collection, processing, analysis and/or submission: --------------------- DATA & FILE OVERVIEW --------------------- The released data consist of two-dimensional (2D) instantaneous velocity fields measured by PIV and a time-averaged 2D velocity and Reynolds shear stress fields. The measurement section of about 0.043 m (horizontal) × 0.17 m (vertical), located downstream about 2 m from the inlet of the flume, is illuminated by a 532 nm continuous-wave laser with 2 watt of output power (LRS-0532, Laserglow Technologies). Total 6,000 images within the FOV filled with seeding particles of 20 μm in diameter are recorded at 20 frames/s using a CMOS camera (2050 × 640 pixels, 8 bits, Flare 2M360 MCL, IO Industries) through a lens (AF Micro-Nikkor 60mm f/2.8D, Nikon). The time delay between subsequent images is set to 0.002 s. We post-processed the recorded images using the open- source PIV software, PIVlab (Thielicke and Stamhuis, 2014), for generating the instantaneous 2D velocity fields at a sampling frequency of 10 Hz. The interrogation window size is 32 × 32 pixels with 50% overlap, generating 39 × 127 velocity vectors in the measurement section. 1. Filename: PIV.n.csv where n=(0-2755) Short description: Instantaneous velocity (2,755 csv files) Long Description: Two-dimensional (2D) instantaneous velocity fields measured by PIV 2. Filename: PIV.time averaged.csv Short description: Time averaged velocity Long Description: Time-averaged 2D velocity and Reynolds shear stress fields ----------------------------------------- DATA-SPECIFIC INFORMATION FOR: PIV.0.csv, PIV.1.csv, ....PIV.2755.csv ----------------------------------------- 1. Number of variables: 4 2. Number of cases/rows: 4,953 3. Missing data codes: Code/symbol 4. Variable List A. Ux = instantaneous horizontal velocity and its unit is meter per second B. Uz = instantaneous vertical velocity and its unit is meter per second C. Points:0 = dimensionless horizontal location of the velocity data D. Points:1 = dimensionless vertical location of the velocity data ----------------------------------------- DATA-SPECIFIC INFORMATION FOR: PIV.time averaged.csv ----------------------------------------- 1. Number of variables: 8 2. Number of cases/rows: 4,953 3. Missing data codes: Code/symbol 4. Variable List A. Ux_average (m/s) = mean horizontal velocity and its unit is meter per second B. Uz_average (m/s) = mean vertical velocity and its unit is meter per second C. Umag (m/s) = mean velocity magnitude and its unit is meter per second D. Reynolds shear stress (m2/s2) = turbulent Reynolds shear stress and its unit is square meter per square second E. Points:0 = dimensionless horizontal location of the velocity data F. Points:1 = dimensionless vertical location of the velocity data G. x (m) = horizontal location of the velocity data and its unit is meter H. z (m) = vertical location of the velocity data and its unit is meter