Inflow Turbulence Generation for Eddy-Resolving Simulations of Turbomachinery Flows

A simple variant of recycling and rescaling method to generate inflow turbulence using unstructured grid computational fluid dynamics (CFD) codes is presented. The method has been validated on large eddy simulation (LES) of spatially developing flat plate turbulent boundary layer. The proposed rescaling algorithm is based on the momentum thickness which is more robust and essentially obviates the need of finding the edge of the turbulent boundary layer in unstructured grid codes. Extension of this algorithm to hybrid Reynolds-Averaged Navier-Stokes (RANS) LES type of approaches and for wall-bounded turbomachinery flows is also discussed. Results from annular diffuser with different inflow boundary layer characteristics are presented as an example application to show the utility of such an algorithm.