Numerical predictions of turbulent flow over a surface-mounted rib

This study accurately predicts cases of turbulent how around a surface-moun ted two-dimensional rib of varying length. The numerical method employs a f inite-difference scheme for integrating the elliptic Reynolds-averaged Navi er-Stokes equations and the continuity equation. The two-equation k - epsil on turbulence model is employed to simulate the turbulent transport quantit ies 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 o f the wall-function approximation. Computations for flow over a surface-mou nted rectangular rib are conducted for varying rib lengths. Results indicat e that upstream of the obstacle the length of the recirculating region rema ins unchanged with varying rib length, while the downstream length of the r ecirculating region is a strong function of rib length and changes nearly l inearly as BIN varies from 0.1 to 4.0. Reattachment on top of the rib, owin g to its increasing length, affects the downstream boundary layer developme nt.