Numerical Predictions of Turbulent Flow over a Surface-Mounted Rib

Abstract

This study accurately predicts cases of turbulent flow around a surface-mounted two-dimensional rib of varying length. The numerical method employs a finite-difference scheme for integrating the elliptic Reynolds-averaged Navier-Stokes equations and the continuity equation. The two-equation \ik–e turbulence model is employed to simulate the turbulent transport quantities and solve the problem. The near-wall regions of the separated sides of the rib are resolved by a near-wall model in a two-layer approach instead of the wall-function approximation. Computations for flow over a surface-mounted rectangular rib are conducted for varying rib lengths. Results indicate that upstream of the obstacle the length of the recirculating region remains unchanged with varying rib length, while the downstream length of the recirculating region is a strong function of rib length and changes nearly linearly as \iB/\iH varies from 0.1 to 4.0. Reattachment on top of the rib, owing to its increasing length, affects the downstream boundary layer development.