ADVANCED ADAPTIVE COMPUTATIONAL METHODS FOR NAVIER-STOKES SIMULATIONS IN ROTORCRAFT AERODYNAMICS

A NEW AND INNOVATIVE CLASS OF ADAPTIVE COMPUTATIONAL PROCEDURES IS TO BE DEVELOPED FOR THE SPECIFIC PURPOSE OF NUMERICALLY-MODELING COMPLEX FLOWS INHERENT IN ADVANCED HELICOPTER-BLADE DESIGNS. THESE PROCEDURES MAKE USE OF MATHEMATICALLY CONSISTENT ESTIMATES OF LOCAL NUMERICAL ERROR, AND AUTOMATICALLY REFINE OR UNREFINE THE MESH OR INCREASE OR DECREASE THE LOCAL SPECTRAL ORDER OF THE APPROXIMATION SO AS TO DELIVER A PREASSIGNED LEVEL OF ACCURACY. THE RESULT IS A SCHEME WHICH ATTEMPTS TO PRODUCE THE BEST POSSIBLE RESULTS WITH THE LEAST NUMBER OF GRID POINTS, DEGRESS OF FREEDOM, AND OPERATIONS. THESE TYPES OF SCHEMES AUTOMATICALLY LOCATE AND RESOLVE SHOCKS, VORTEX INTERACTIONS, VISCOUS BOUNDARY LAYERS, AND OTHER FLOW DETAILS TO AN ACCURACY LEVEL SPECIFIED BY THE USER OF THE CODE. THEY ALSO ARE CAPABLE OF ELIMINATING ARTIFICIAL VISCOSITY IN REGIONS WHERE VORTICAL EFFECTS ARE SIGNIFICIANT. THE PHASE I WORK INVOLVES A FEASIBILITY STUDY OF COMBINED H-SPECTRAL ADAPTIVE METHODS FOR DYNAMIC ROTORBLADE FLOWS, WITH EMPHASIS ON ACCURATE SIMULATION OF VORTEX INITIATION, MIGRATION, AND INTERACTION. THE MAJOR COMPONENTS OF A WORKING COMPUTER PROGRAM BASED ON THESE SCHEMES WILL BE DEVELOPED AND TESTED IN PHASE I.