Fuselage-Rotor Mutual Interference: a Step Towards Interactional Aerodynamics in Comprehensive Codes

An analytical formulation of the induced velocities caused by the fuselage shell of the HART II wind tunnel model in the vicinity of the rotor is derived from computational fluid dynamics (CFD) velocity data. The analytical induced velocity model can directly be used to account for the inflow at the blade elements and also allows for analytical integration to compute the associated displacements of rotor blade tip vortices convecting downstream through this velocity field. The implementation is demonstrated at the example of the rotor simulation program S4 of the German Aerospace Center (DLR) in Braunschweig. The model’s influence on the major flow field variables around the rotor disk and the wake trajectory is demonstrated. Since the method is generic it is anticipated that the effect of any kind of fuselage can be accounted for this way and it may be used within any comprehensive code, prescribed wake code, and even free-wake codes.