DRAG REDUCTION ON AN EJECTION SEAT DURING HIGH SPEED EJECTION

A PROGRAM OF WORK LEADING TO AN ANALYTICAL COMPUTATIONAL FLUID DYNAMICS (CFD) CAPABILITY TO PREDICT THE DETAILED FLUID MECHANICS OF AN EJECTION SEAT DURING HIGH SPEED EJECTION IS DESCRIBED. THE METHOD WILL CONSIDER TRANSONIC FLOWS AT HIGH DYNAMIC PRESSURES INCLUDING EFFECTS OF SHOCK WAVES AND POSSIBLE TRANSIENTS IN THE STAGNATION ZONE. THE PROPOSED ANALYSIS PROCEDURE, USING EXISTING TECHNOLOGY, WILL INVOLVE SOLUTIONS OF THE NAVIER-STOKES EQUATIONS FOR UNSTRUCTURED MESHES SURROUNDING THE COMPLEX CONFIGURATIONS CORRESPONDING TO MODERN EJECTION SEATS WITH AN OCCUPANT. THE PHASE I STUDY WILL DEMONSTRATE THE FEASIBILITY OF USING ADVANCED COMPUTATIONAL TECHNIQUES TO PREDICT THE AERODYNAMIC FORCES AND MOMENTS ON THE SEAT DURING HIGH SPEED EJECTION, AND PREDICTED DETAILS OF THE ASSOCIATED FLOW FIELD WILL GIVE INSIGHT INTO DESIGN IMPROVEMENTS SUCH AS DRAG REDUCTION AND REDUCED WINDBLAST LOADS.