Three-dimensional Navier-Stokes computation of turbomachinery flows using an explicit numerical procedure and a coupled k-ε turbulence model

An explicit, three-dimensional, coupled Navier-Stokes/k-ε technique has been developed and successfully applied to complex internal flow calculations. Several features of the procedure, which enable convergent and accurate calculation of high Reynolds number two-dimensional cascade flows have been extended to three-dimensions, including a low Reynolds number compressible form of the k-ε turbulence model, local timestep specification based on hyperbolic and parabolic stability requirements, and eigenvalue and local velocity scaling of artificial dissipation operators. A flux evaluation procedure which eliminates the finite difference metric singularity, at leading and trailing edges, on H- and C-grids, is presented. The code is used to predict the pressure distribution, primary velocity and secondary flows in an incompressible, turbulent curved duct flow for which CFD validation quality data is available.