CALCULATION OF HELICOPTER ROTOR BLADE/VORTEX INTERACTION BY NAVIER-STOKES PROCEDURES (P85-27)

THE PROPOSED EFFORT WOULD INVESTIGATE THE PROBLEM OF A VORTEX INTERACTING WITH A HELICOPTER ROTOR BLADE SECTION. THIS WOULD REPRESENT THE FIRST STEP IN APPLYING THE THREE-DIMENSIONAL, NAVIER-STOKES EQUATIONS TO THE TRANSONIC ROTOR BLADE/VORTEX INTERACTION EFFECTS ON HELICOPTER PERFORMANCE AND NOISE. THE INNOVATION OF THE PROPOSED EFFORT LIES IN THE REMOVAL OF RESTRICTIONS IMPOSED BY THE USUAL INVISCID APPROACHES TO THIS PROBLEM. THE VISCOUS EFFECTS WOULD BE INCLUDED IN THE COMPUTATIONS THUS ALLOWING THE VORTEX STRUCTURE TO CHANGE AS THE FLOW PROCEEDS DOWNSTREAM AND ALLOWING BLADE VISCOUS DISPLACEMENT EFFECTS TO INFLUENCE THE VORTEX PATH. UNDER PHASE I, THE EFFORT WOULD CONCENTRATE ON THE INVESTIGATION OF THE UNSTEADY THREE-DIMENSIONAL FLOW ASSOCIATED WITH THE INTERACTIONS OF BLADE WITH VORTICES FOR REPRESENTATIVE THOUGH SIMPLIFIED GEOMETRY AND FLOW CONDITIONS. LATER EFFORTS WOULD EXTEND THE PRESENT PROPOSED INITIAL EFFORTS TO MORE REPRESENTATIVE GEOMETRY AND FLOWS. WHEN COMPLETED, THE DEVELOPED NUMERICALPROCEDURE WOULD BE CAPABLE OF SIMULATING THE UNSTEADY TRANSONIC ROTOR BLADE/VORTEX INTERACTIONS TO DETERMINE ITS EFFECTS ON THE PERFORMANCE, VIBRATIONAL PROBLEMS AND AEROACOUSTICS ASSOCIATED WITH A MODERN HELICOPTER. THE PROCEDURE WOULD ACCOUNT FOR VISCOUS EFFECTS INCLUDING FLOW SEPARATION AND SHOCK-BOUNDARY LAYER INTERACTIONS AND WOULD ALLOW FOR REALISTIC BLADE AND TIP GEOMETRIES.