Effect of leading waves on velocity distribution of undular bore traveling over sloping bottom

For providing new insights into the effect of the leading waves on the velocity distribution of the generated bore, a case study of the undular bore (or weak bore) with the water depth ratio 1.70 is tested in a flume, using flow visualization technique (FVT) and high-speed particle image velocimetry (HSPIV). The undular bore, generated right downstream of a suddenly lifted gate, propagates first over a horizontal bottom and then travels over a 1:20 sloping bottom. The wave gauges were used to measure the free surface elevations of the generated bore at different positions.