Numerical simulation of turbulent flow in helically coiled open-channels with compound cross-sections

摘要

Turbulence structure in a helically coiled open channel flow is numerically simulated using three different turbulence models-the Launder and Ying model, the Naot and Rodi model, and the nonlinear kappa-epsilon model (SY model). Simulation results were compared with observation of (i) turbulent flows in alternating point-bar type channel bends with rectangular sections, and (ii) straight open channel flows with compound cross-sections. Based on calculations of the impact of various channel curvatures on turbulence characteristics, accuracy of the three turbulence models was analyzed with observed data as a qualitative reference. It has been found out that the Launder and Ying model and the nonlinear kappa-epsilon model are able to predict the same general trend as measured data, and the simulation of the effect of the centrifugal force on the formation of secondary currents produces a correct pattern.