Abstract: The energy dissipation of vertical-slot fishway is concentrated near the slot. Due to the shrinkage and constraint of the slot, vortex is generated, and the flow in the fishway is made faster and tangled. In order to improve the hydraulic characteristics of fishway pool room, the RSM(Reynold’s stress model) was applied to numerically simulate the same side of vertical-slot fishways of different structures. Results suggest that a cylindrical barrier in the pool at the slot exit could help attenuate the velocity gradients at the slot, and reduce the turbulent kinetic energy and Reynolds shear stress by 20%-30%. The hydraulic characteristic of this fishway is stable and it could meet the hydrodynamic requirements of more fishes passing through the dam.

Key words: vertical slot, fishway, structural variation, numerical simulation, Reynold’s stress model