Transonic flutter simulations using an implicit aeroelastic solver

Flutter computations are presented for the AGARD 445.6 standard aeroelastic wing configuration using a fully implicit, aeroelastic Navier-Stokes solver coupled to a general, linear, second-order structural solver. This solution technique realizes implicit coupling between the fluids and structures using a subiteration approach. Results are presented for two Mach numbers, M-infinity=0.96 and 1.141. The computed flutter predictions are compared with experimental data and with previous Navier-Stokes computations for the same case. Predictions of the flutter point for the M-infinity=0.96 case agree well with experimental data. At the higher Mach number, M-infinity=1.141, the present computations overpredict the flutter point but are consistent with other computations fur the same case. The sensitivity of computed solutions to grid resolution, the number of modes used in the structural solver, and transition location is investigated. A comparison of computations using a standard second-order accurate central-difference scheme and a third-order upwind-biased scheme is also made.