Prediction of Flutter and LCO by an Euler Method on Non-moving Cartesian Grids with Boundary-Layer Corrections

We present an unsteady Euler method on non-moving cartesian grids coupled with an integral boundary-layer method for the prediction of flutter. The Isogai 2-D wing model are computed by 5 methods: (1) Euler method on the non-moving cartesian grid without the boundary-layer correction; (2) Euler method on body-fitted moving grids without the boundary-layer correction; (3) Euler method on the non-moving cartesian grid coupled with the integral boundary-layer method; (4) Euler method on body-fitted moving grids coupled with the integral boundary-layer method; (5) Full Navier-Stokes method on body-fitted moving grids. Comparisons will be made of the computed flutter boundary and frequency as well as LCO magnitude versus speed index at various transonic Mach numbers. The effect of viscosity and the applicability of the Euler method on non-moving cartesian grids with approximate boundary conditions are assessed. I