Measurement of atmospheric boundary layer based on super-large-scale particle image velocimetry using natural snowfall
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We present an implementation of super-large-scale particle image velocimetry (SLPIV) to characterize spatially the turbulent atmospheric boundary layer using natural snowfall as flow tracers. The SLPIV technique achieves a measurement area of ~22 m × 52 m, up to 56 m above the ground, with a spatial resolution of ~0.34 m. The traceability of snow particles is estimated based on their settling velocity obtained from the wall-normal component of SLPIV velocity measurements. The results are validated using coincident measurements from sonic anemometers on a meteorological tower situated in close proximity to the SLPIV sampling area. A contrast of the mean velocity and the streamwise Reynolds stress component obtained from the two techniques shows less than 3 and 12 % difference, respectively. Additionally, the turbulent energy spectra measured by SLPIV show a similar inertial subrange and trends when compared to those measured by the sonic anemometers.
KeywordsParticle Image Velocimetry Atmospheric Boundary Layer Settling Velocity Light Sheet Particle Image Velocimetry Measurement
This work was supported by US Department of Energy (grant No: DE–EE0002980) and the resources provided by the University of Minnesota College of Science and Engineering, Department of Mechanical Engineering and St. Anthony Falls Laboratory as part of the start-up package of Jiarong Hong.
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