A PC-PLATFORM TOOL FOR IMPROVING AEROELASTIC PREDICTIONS

Abstract

The use of linear aerodynamic theories in aeroelastic analyses in the transonic speed range is not adequate because of the occurrence of shock waves. On the regime usually requires long solution times on expensive large computers. In this work, a PC platfonn-based aeroelastic prediction tool with reasonable run-time is developed using computational aeroelasticity techniques. The developed tool is used to predict divergence and flutter speeds of several typical sections and finite aircraft wings at different Mach numbers in the transonic and low supersonic flow regimes. The Euler equations were selected as an aerodynamic model in aeroelastic analyses because of their adequate accuracy in predicting transonic flow tields and suitability for PC-platform computations from both storage and run-time points of view. A steady and an unsteady two-dimensional Euler solvers are developed using Van Leer flux vector splitting algorithm and approximate factorization scheme. In this scheme, spatial derivatives are approximated by MUSCL-type differencing. The solvers are validated against published test cases of the NACA 0012, and NACA 64AOIO conventional airfoils. The developed steady two-dimensional Euler solver is used to solve typical-section static aeroelastic problems for different typical section characteristics. In order to

solve the nonlinear static torsional equilibrium equation, a special trial and error procedure is developed to compute the final elastic angle of attack. The effects of certain aeroelastic parameters on divergence speed are studied for a wide range of Mach numbers.