Simulation of Unsteady Rotor-Fuselage Interactions Using Unstructured Adaptive Meshes

A three-dimensional parallel Euler flow solver has been developed for the simulation of unsteady rotor-fuselage interaction aerodynamics on unstructured meshes. To simulate the unsteady rotor wake effectively, the flow field is divided into a moving zone rotating with the blades and a stationary zone containing the fuselage. A sliding mesh algorithm is applied for the convection of flow variables across the cutting boundary between the two zones. Quasi-unsteady mesh adaptation is adopted to enhance the spatial accuracy of the solution. Mesh deformation due to blade motion in forward flight is handled by using the spring analogy and cell edge-collapsing. Validation of the rotor-alone configuration was made for the AH-1G rotor in forward flight. The rotor-fuselage interaction study was made for flow around the Georgia Tech configuration and the ROBIN fuselage. It is shown that the present method is efficient and robust for the prediction of complicated unsteady rotor-fuselage interaction phenomena.