Stereoscopic MicroPIV Measurements in A Labyrinth-Channel Dripper Used in Micro-Irrigation Systems

Small serpentine-shaped channels used in drip irrigation is an efficient irrigation technique in order to spare water. Eventual clogging in such micro channels should be avoided to extend the lifetime of these irrigation systems. Clogging often occurs when sedimentation takes place in low or zero velocity regions in steady laminar flow conditions. For this reason, labyrinth dripper designs are used to enhance mixing and / or induce unsteady flow conditions inside the channel. The aim of the present study is to investigate the flow inside such millimetric complex channel geometry with Stereoscopic MicroPIV measurements. Current three-component (3C) velocity measurements are compared with previous two-component (2C) velocity measurements. Results indicate that the u and v components of the 3C measurements are in good agreement with the previous 2C measurements, identifying and confirming the previously measured low- and zero-velocity regions. Furthermore, the out-of-plane (w) velocity component adds new information about the flow field revealing three-dimensional (3D) flow structures, what appears to be oblique vortices emanating from the baffle tips. In conclusion, both enhanced mixing due to 3D vortices and induced unsteady flow field seems to be responsible for clogging suppression.