Predicting Rotor BVI Loads Inclusive of the Fuselage Effect using an Unstructured Mesh Technique

Abstract

Viscous flow simulations of the HART II rotor were conducted using a flow solver based on unstructured meshes. To capture the blade-vortex interaction (BVI) phenomena accurately, a series of solution-adaptive mesh refinements was carried out. The blade deformation was considered using the HART II rotor measurement. Calculations were made for isolated-rotor and rotor-fuselage configurations, to investigate the fuselage effect on the blade loading and the rotor wake structure. The inclusion of fuselage significantly improves the trim control prediction, which results from the more accurate prediction of rotor inflow at the front and rear portions of the rotor disk. This improved trim control also leads to an improvement in the blade loading prediction for the rotor-fuselage configuration. From the solution-adaptive mesh refinement study, it was found that high-frequency blade loading caused by BVI can be obtained more accurately as the mesh is further refined, whereas the low-frequency loading is mostly independent to the mesh resolution. The predicted vortex core positions at the retreating side of the rotor were well matched with measurements, whereas a relatively large difference between the prediction and the measurement was observed at the advancing side.