An Experimental Study of Flow Structures in a Pool-weir Fishway

Three-dimensional velocity distributions in a pool-weir fishway were systematically measured by Acoustic Doppler Velocimeter (ADV). The experimental study was carried out in a perspex flume, which could be divided into three sections, i.e., inflow section, working section and outflow section. The working section mainly contained 4 pools, which exhibited a stepped layout from the lower pool to the upper pool, and a fall between the adjacent pools was 5cm. Each pool was 90cm long, 60cm wide and 100cm deep. The experimental flow rates were 20.79L/s and 30.04L/s, respectively. For each flow rate, different horizontal planes, different cross-sections and different spacing were arranged. Through the experimental study, characteristics and similarities of longitudinal, vertical and transverse velocity distributions at different depths and on different horizontal and vertical planes were analyzed and compared. Variation in the maximum longitudinal velocity along flow direction and locations of the maximum velocities at different vertical lines were given.

Keywords: fishway; pool-weir flow; 3D velocity distributions; ADV measurements.