Author(s): Joongu Kang; Hongkoo Yeo; Sungjung Kim; Un Ji
Keywords: Flow separation; impermeable groin; permeable groin; pile groin; recirculation zone; triangular-shaped groin
Abstract: The results of an experimental study on the flow characteristics around a groin structure of various geometries and permeabilities are presented. The impermeable rectangular, the permeable pile, and the triangular-shaped groins are considered. The velocity fields were observed using large-scale particle image velocimetry, whereas the maximum velocities were measured using an acoustic Doppler velocimeter. An increased velocity at the groin tip and a broad range of the recirculation zones were observed for the impermeable rectangular groin. For the permeable pile groin, the velocity at the groin tip, the vortex strength, and the scale of the recirculation zone tended to decrease as the openings between the piles increased. Also, the triangular-shaped groin formed narrower and longer recirculation zones compared with the permeable pile groin of identical cross-sectional flow area. These quantitative findings on the flow patterns for groins of various geometries and permeabilities are practically important to design and evaluate their performance in field applications.