Numerical study of turbulent flow over two-dimensional surface-mounted ribs in a channel

Abstract

This study accurately predicts the cases of turbulent flow around a surface-mounted two-dimensional rib with varying lengths. The numerical method employs a differencing scheme for integrating the elliptic Reynolds-averaged Navier–Stokes equations and the continuity equation. A two-equation k–ε turbulence model is employed to simulate the turbulent transport quantities and close the solving problem. The near-wall regions of the separated sides of the rib are resolved by a near-wall model of a two-layer approach instead of the wall function approximation. Computations for flow over a surface-mounted rectangular rib are conducted for the variations in the rib lengths. Results indicate that upstream of the obstacle, the length of the recirculating region remains unchanged with varying rib lengths; while the downstream length of the recirculating region is a strong function of rib length and changes nearly linearly for the varying lengths of B/H=0.1 to B/H=4.0. Reattachment on top of the rib, owing to its increasing length, affects the downstream boundary layer development. Copyright © 1999 John Wiley & Sons, Ltd.