Forced convection over a three-dimensional horizontal backward facing step

Forced convective flow over a 3-D backward-facing step is studied numerically. The momentum and energy equations were discretized by means of a finite volume technique. The SIMPLE algorithm scheme was used to link the pressure and velocity fields in the entire domain and a line-by-line scheme was used in each plane to compute the velocity, pressure, and temperature field distributions. The code was validated by comparing numerical predictions with experimental data for flow over a 3-D backward facing step that is available in the literature. Flow of air (Pr = 0.70) over a three-dimensional horizontal backward-facing step geometry with an aspect ratio AR = 8 and an expansion ratio ER=2 was considered. The stepped wall downstream of the expansion was heated by subjecting it to a constant heat flux (q_w = 50 Wm⁻²) and the other walls were considered as insulated. The inlet flow was taken to be hydro-dynamically fully developed with a uniform temperature profile. Locations where the stream wise velocity and the span wise velocity components are zero for the nearest plane adjacent to the stepped wall were plotted for different Reynolds numbers. Distributions for local and average Nusselt number for the stepped wall, and graphical representations for u, v, and w velocities components obtained in these simulations are presented in the paper.