The main reason of the stepped spillway having greater energy dissipation is tha there is big horizontal vortex in the inner angel of the steps and it makes momenbo exchange with outer mainstream then accelerates the theulence in the water 由于阶梯的存在，使得水流在阶梯凹角内产生强烈的水平横轴旋涡，旋滚水流与外部主流之间不断进行的动量交换加剧了水流内部的紊动，从而使阶梯溢流坝有较高的消能率。
