Calculations of flow over a step

Finite element codes are described for transient analysis of flow over a backward facing step. Attention is given to a Galerkin method for a weak form of the basic equations. The CONDIF program employs four-node quadrilateral elements with bilinear velocity interpolation and uniform pressure throughout an element. The CONVEC code features nine-node elements with biquadratic interpolation for the velocity components and bilinear interpolation for the pressure, which is discontinuous between elements. The time step iterations are achieved with a finite difference scheme, while fractional steps are applied to the momentum equations. A weak treatment is used for the tangential velocity to avoid checkerboard splitting of the pressure field. Sample reslts are provided for wall shear and extreme velocity values.