Three Dimensional Numerical Simulation of Vortex Structures in Barak River

Abstract

Natural channel have complex three dimensional flow structures particularly at the outer bank cell due to the combined effects of secondary currents and higher velocity profiles. In this paper Computational fluid dynamics is used to study the meandering bend of the Barak River. Numerical modeling is done using Reynolds averaged continuity and Navier Stokes equation. These equations are solved by finite volume method. Appropriate representation of counter-rotating secondary flow in the channel bend requires both the suitable treatment of the free water surface and a turbulence model that can resolve the anisotropy of turbulence. Hence the volume of fluid method (VOF) was used to model the free surface and reynolds stress turbulence model (RSM) has been used to close the RANS equations. Higher velocity profiles were prominent at the outer bank. Skew induced stream wise vorticity was observed close to the outer bank which confirms the existence of corner induced secondary current. The vortices formed were found to be of Prandtl’s first kind.