Abstract
Turbulence measurements in side-cavity open-channel flows with various open-mouth shapes were conducted., by making use of PIV and LDA. The water-surface fluctuations in the side cavity, at the junction and in the main channel were measured simultaneously by three sets of super-sonic wave gauges. In the case of no partition plate, a vortex which was generated by the shear instability moves in the downstream. The scale of its vortex increases in the downstream. In the case of narrow open mouth, a stable vortex is generated inside of the side cavity. In contrast, in the case of wide open mouth, when a high-momentum water bulge moves from the main channel into the side cavity, the water surface moves upward in the side cavity. This semi-periodical phenomena associate strongly with seiche motions.
