An Evaluation of the Influence of the Test Facility on Rotor Performance Characteristics

The development of new rotor designs, including innovative active controls, is usually accomplished in enclosed test facilities with reduced scale rotors. Experimental evaluations have shown that the test facilities can influence performance parameters. Computational methods that resolve the Reynolds-averaged Navier- Stokes (RANS) equations may provide an efficient approach to examine these influences and extrapolate the model-scale results to full-scale. This work examines the requirements in applying a RANS-based solver to capture the physics of the rotor-hover test facility interactions, including an assessment of the performance changes. The computational simulation including the test facility requires a large number of rotor revolutions to allow the room physics to converge. False convergence is observed while corner vortices migrate. Full convergence can require up to six times the computational time needed for a rotor-alone simulation for a rigid rotor.