DYNAMIC STALL CONTROL

COMPUTATIONAL ALGORITHMS AND CODE WILL BE DEVELOPED FOR CALCULATING UNSTEADY COMPRESIBLE 3-D VISCOUS FLOW AND RETREATING-BLADE DYNAMIC STALL ON MODERN HIGH-PERFORMANCE HELIOPTER ROTORS. THE ALGORITHM DEVELOPMENT WILL START FROM AN EXISTING 3-D TIME DEPENDENT VISCOUS COMPRESSIBLE CODE ALREADY USED SUCCESSFULLY TO CALCULATE PERIODIC PITCHING OF A SWEPT WING SECTION MOUNTED IN A WIND TUNNEL TEST SECTION. THE CODE USES AN APPROXIMATE FACTORIZATION (AF) ALGORITHM (INCLUDING CROSS DERIVATIVE TERMS) IN A MOVING BOUNDARY FITTED CORDINATE SYSTEM WITH SOLUTION ADAPTIVE GRID GENERATION ALGORITHMS, AND IS HIGHLY VECTORIZED FOR THE CRAY-2. THE NEW CODE WILL INCLUDE THE MORE DIFFICULT GEOMETRY DESCRIPTION OF A FINITE SPAN WING, AND TURBULENCE MODELING FOR STRONGLY SEPARATED FLOWS INCLUDING CENTRIFUGAL FORCES. THE PHASE II CODE WILL ALSO BE APPLICABLE TO COMPLEX MOTIONS AND TO FULLY COUPLED AEROELASTICITY CALCULATIONS.