Numerical simulation and intelligent computing of negative pressure on step surface of stepped spillway dam

In order to verify the effect of negative pressure on step surface of stepped spillway dam with different aeration facilities, the four schemes were studied by a three-dimensional RNG κ-ε model of the VOF method. Four schemes were are: (1) even steps with no bucket aerator; (2) even steps with bucket aerator (prototype scheme); (3) first big step with no bucket aerator; (4) first big step with bucket aerator. The results indicate that there is large negative pressure on WES surface and stepped spillway surface in scheme 1 and 3. Scheme 3 can reduce the pressure on stepped spillway, while it increases the pressure on WES surface. On WES surface, there is a maximum pressure of -4.32 kpa and -5.03 kpa in scheme 1 and 3 respectively. On stepped spillway surface, there is a maximum pressure of -11.1 kpa and -9.19 kpa in scheme 1 and 3 respectively. As for scheme 2 and 4, there is no negative pressure at the downstream of WES surface and stepped spillway surface. The maximum negative pressure occurs at the first step, which is -9.52 kpa and -0.842 kpa in scheme 2 and 4 respectively. The combination of first step with bucket aerator in scheme 4 can effectively increase the energy dissipation rate, and significantly reduce the distribution and value of the negative pressure on stepped spillway surface.