UNSTEADY PANEL METHOD CALCULATION OF PRESSURE DISTRIBUTION ON BO-105 MODEL ROTOR BLADES

An unsteady 3-D Panel method has been developed to compute the subsoni c aerodynamics of finite thickness multi-bladed rotors, The full span free wake of the blades is simulated by a lattice of shed and trailing vortices. The method is applied to a two-bladed and the four-bladed B O 105 hingeless rotor in hover. The four-bladed rotor has also been st udied in the forward flight descent and climb modes., Prediction of pr essure distribution on blade surface during hover agrees very well wit h wind tunnel test data and Euler solver results, Results for descent flight where severe blade vortex interaction (BVI) takes place are in fair agreement with the experiment, Also results for the climb mode co rrelate well with test data. The time-stepping scheme employed permits a detailed study of the wake development. This is done for the descen t case to indicate areas of possible severe BVI. No restrictions are p laced on the prescribed blade motion, blade profile, planform, twist e tc. so that a single code can treat multiblade rotors in a variety of flight conditions.