Experimental investigation of channel flow through rigid roughness elements with different shapes

Mean velocity was measured using a 3D micro ADV, collected at each experiment point for 2min with a sampling frequency of 25 Hz. The utilized ADV, which has a forward-looking probe, was mounted on a movable platform over the flume and was able to move in the longitudinal and transverse directions. The vertical adjustment of the device was set according to a custom-made positioning system.