Nonlinear Iteration Methods for High Speed Laminar Compressible Navier Stokes Equations

Full Newton nonlinear iteration is compared to use of a defect correction approach rst order Jacobian second order residual for solving the steady state compressible ow equations The Jacobian is constructed numerically and solved using a PCG type method with block ILU k preconditioning Numerical tests are carried out using the NACA airfoil at various free stream Mach numbers and Reynolds numbers The full Newton approximation is generally more robust and takes less CPU time than the defect correction approach No particular di culty was observed in solving the full Newton Jacobian using an ILU unknowns with CGSTAB acceleration