Investigating the Effects of Partial Deviation of Acoustic Doppler Velocimeter on Measured Flow Characteristics

Acoustic Doppler Velocimeter is one of the most widely used devices in hydraulic laboratories for measuring 3D flow characteristics. The holder of these devices may be slightly deflected over time or during initial installation, and the ADV receivers may not be exactly parallel to the flume. This study investigates the effects of ADV deviation on measured values of flow characteristics. For this purpose, a technician has installed the ADV device on the flume. Partial deviations in both horizontal and vertical planes are measured accurately. Velocity profile was measured in the center of the channel. The results showed that 2 mm deviation in horizontal and vertical planes causes 240% and 67% error in measuring the transversal and vertical velocities, respectively. The effect of deviation on turbulence intensity is significant. Besides, this deviation causes 148% error in Reynolds shear stress measurements. A comparison between measured profiles and global distribution of different parameters shows big difference between them. Finally, the proposed equations to correct the instantaneous 3D velocities perform well and can be used as post-processing tool.