Influence Study of the Entrance Channel in a Two-Dimensional Backward-Facing Step Flow

Abstract

The influence of the entrance channel in the numerical simulation of the classic two-dimensional backward-facing incompressible step flow was studied. Locations of detachment and reattachment, as well as velocity profile, were obtained as functions of Reynolds number. The Unified Finite Approach Exponential-type Scheme (UNIFAES) was employed in the discretization of the advective and viscous fluxes of the Navier-Stokes equations in primitive variables. The almost unknown semi-staggered mesh was used. The momentum equations are integrated explicitly after the solution of a Poisson pressure that enforces mass conservation. Richardson extrapolation is employed to estimate the correct solutions. As could be expected, using the entrance channel provided better agreement with experiments than not using it, particularly for producing a non-symmetric, decentralized flow profile at the step plane, instead of the assumed symmetric profile. Also, the size of first bubble is smaller, and the size of the second bubble is bigger.