The prediction and validation of hover performance and detailed blade Loads

This paper focuses on the validation of a hybrid computational fluid dynamics (CFD) method for the prediction of isolated rotor hover performance of the model UH-60A and tapered-tip variant rotors by comparison with available data sets. The hybrid method combines a local Reynolds-averaged Navier-Stokes solver to resolve the near-blade flow, with a vorticity-embedding potential flow solver for the wake flow field. The comparisons entail wake trajectories, surface pressures, integrated sectional thrust and torque, and rotor performance. The wake and loads comparisons demonstrate that the current method has a predictive accuracy and speed that is unusual to most CFD methods. The resulting performance comparisons are inconclusive owing partially to the fact that two available data sets do not agree to the level of accuracy required for validation. It appears therefore that development of hover CFD methods requires validation and test data in greater detail and variety than currently exists.