ABSTRACT
The effect of micro groins on the velocity distribution was investigated in a flume with rectangular cross-section in experiments with fixed and mobile bed representing coarse sand. ADV and Particle Image Velocimetry were used to measure the 3D flow field and surface flow velocities respectively and similar results were obtained. Similar experiments were carried out for three different setups: a reference experiment without groins, an arrangement with a single groin and four serial groins. The results show a significant velocity reduction at the protected bank and a slight increase at the opposite bank after the implementation of the groins. In the runs with mobile bed, scours developed near the groin heads and directly upstream the root whereas deposition occurred along the protected bank downstream of the groin. The influence on the flow field and the bed morphology was more pronounced with a serial arrangement of groins.
