ADVANCED COMPUTATIONAL FLUID DYNAMICS METHODS FOR ELASTIC HELICOPTER BLADES

CURRENT RESEARCH IN ROTORCRAFT ANALYSIS DISCIPLINES HAS BEEN EXTENSIVE BUT IN PARALLEL PATHS. SPECIFICALLY, ON GOING RESEARCH CONTINUES IN COMPUTATIONAL FLUID DYNAMICS (CFD) FOR THE NONLINEAR AERODYNAMIC ANALYSIS OF ROTOR BLADES AND COMPUTIONAL STRUCTURAL DYNAMICS (CSD) FOR THE NONLINEAR STRUCTURAL DYNAMIC ANALYSIS OF COMPOSITE ROTOR BLADE. CFD CODES BASED ON TRANSONIC SMALL DISTURBANCE, FULL POTENTIAL, EULER, AND NAVIER-STROKES THEORY BEING DEVELOPED. SIMILARLY, CDS CODES BASED ON MODAL ANALYSIS AND FINITE ELEMENT THEORY RESOLVED. ONE METHOD IS TO "TIGHTLY" COUPLE THE TWO DISCIPLINE. THAT IS, USE THE CFD CODE TO PREDICT THE UNSTEADY AERODYNAMIC FORCES ACTING ON THE STRUCTURE BASED ON THE KNOWN POSITION AND VELOCITY OF THE BLADES. THE OBJECTIVE OF THIS STUDY IS TO PROTOTYPE A "TIGHT" COUPLING METHOD BETWEEN CFD AND CSD CODES. THE FPR CODE HAS BEEN SELECTED TO REPRESENT THE CFD CODES, AND 2GHAS HAS BEEN SELECTED TO REPRESENT THE CSD CODES. DYMORE WILL BE USED IN THE PHASE I ACTIVITY INSTEAD OF 2GHAS. AFTER THE THEORETICAL DEVELOPMENT, A MODULAR SOFTWARE WILL BE DESIGNED AND IMPLEMENTED TO ACCOMPLISH THE "TIGHT" COUPLING BETWEEN FPR AND DYMORE. THE COUPLED CODES WILL BE TESTED FOR NUMERICAL STABILITY AND CONVERGENCE. THE PUMA BLADE MODELED IN [1] WILL BE USED TO DEMONSTRATE THE PROOF OF CONCEPT. FINALLY TASKS IN SIMILAR COUPLING BETWEEN FPR AND 2GHAS CODES WILL BE IDENTIFIED AND A SOLUTION PROCEDURE WILL BE PROPOSED.