Abstract
During the flood, high-velocity flow sometimes generates large surface waves called " triangular wave train", which look like the jagged plates on the back of a dinosaur. These waves cause local erosion of riverbed and may have great destructive effects on revetment blocks. Although the wave train is thought as one of the surface waves on antidunes, study on their occurrence condition have not been sufficiently conducted. In this paper, we made the flume experiment to understand the occurrence condition of triangular wave. The experimental results showed that the triangular waves were generated when Shield number is larger than 0.15 and Frude number is in the range of 1.0 to 1.7. The number of waves train increased with the increase in the ratio of width and depth.
