A211 ステレオ撮影による開水路水面変動の画像計測

抄録

When a portion of a straight open-channel is replaced by a channel with a side cavity zone, water surface in the main channel in front of the cavity as well as that within the side cavity zone begins to show significant surface oscillation for specific experimental conditions. The mode of the oscillation changes with hydraulic condition and aspect ratio of the side cavity shape. When the aspect ratio is small, only a seiche-like oscillation within the cavity zone can be observed. However, as the streamwise length of the cavity increases, i.e. for a large aspect ratio, the oscillation in the cavity zone propagates into the main channel and a longitudinal oscillation becomes evident. In order to understand the mechanism of such mode-change, we performed a stereoscopic measurement of the water surface flow oscillation by gradually changing the aspect ratio of the side cavity.