Particle image velocimetry studies around a rectangular body close to a plane wall

Flow structures around a rectangular body located close to a ground board in a free-surface water channel were investigated using the particle image velocimetry (PIV) technique. The rectangular body is set with α=0°α=0° and α=10°α=10° yaw angles referenced to the flow direction, and measurements were performed on the vertical and horizontal planes. The PIV technique provided instantaneous and time-averaged flow fields for Reynolds number ReH=1.2×104 based on the model height. For α=0°α=0°, the results indicate that the flow structure in the wake region vary significantly with the elevation level from the ground surface. An asymmetric large circulating flow region is identified in the wake region for α=10°α=10°. The instantaneous flow fields reveal the presence of small-scale vortices in the main flow over the separation line. These small-scale vortices coalesce to form larger-scale vortices.