Unsteady Reynolds-Averaged Navier–Stokes Simulation of Crossflow Rotors, Scaling, and Blockage Effects

Abstract

This work presents results and analysis of H-type crossflow rotors using unsteady Reynolds-Averaged Navier–Stokes (URANS) computational fluid dynamics simulations. It is demonstrated that, with an efficient solver, robust high-fidelity time-resolved solutions can be obtained with computational speed and cost that allow the use of high-fidelity computational fluid dynamics in the early stages of a new design. The sensitivity of power prediction on the far-field boundary condition proximity is also shown and an analytical justification is given for this behavior based on blockage effects. The effects of physical scaling over a range of Reynolds numbers between and of four geometrically similar turbines of differing solidity are studied. Significant improvement in power efficiency can be achieved as the Reynolds number increases when turbines are scaled to very large size. Power curves for all test cases, unsteady blade loads for select cases, and effects of three-dimensionality are provided to aid future work.