Experimental study of side looking ADV probe accuracy in a turbulent flow field

One of the practical and useful techniques for the flow field measurement in open channels is Acoustic Doppler Velocimeter (ADV). Presence of ADV probe and its holding system against flow disturb natural flow pattern which can change turbulent flow structure. Thus, the error of the Acoustic Doppler Velocimeter is consist of its intrinsic error and the presence of ADV against flow. To have better understating about this effect, in this paper, flow field in an open-channel is measured using Particle Image Velocimetry (PIV) technique and side-looking ADV probe. The results show that sreamwise velocity obtained from both methods are in good agreement and on average, there is 5 percent difference, while vertical and lateral components of velocity are considerably different. Also, comparison of sreamwise and lateral turbulence intensities and the Reynolds shear stress shows lower differences for measured points near the water surface and the differences increase approaching to the bed.