Role of Turbulence Model in Prediction of Pump-Bay Vortices

A numerical model was developed by the writers to simulate the flow in a water-pump intake bay. Among the flow features of interest are subsurface vortices attached to the walls of the channel, and free-surface vortices. Such vortices are observed in laboratory models. This technical note is concerned with the role of the turbulence model and influence of wall roughness in the prediction of location, size and strength of different types of vortices, and the level of swirl in the intake pipe. Calculations made with the k-epsilon and the k-omega models were found to predict vortices of similar shape and size, but their locations and strength depended on the turbulence model and treatment of the near-wall flow. Weaker vortices were predicted when wall roughness was taken into account, raising the possibility of using roughness as a vortex suppression device.