ROBUST LINEAR AND NONLINEAR STRATEGIES FOR SOLUTION OF THE TRANSONIC EULER EQUATIONS

Full Newton nonlinear iteration using a Jacobian based on a high order discretization is compared with a widely used technique which uses a first order Jacobian. The linearized equations are solved using a level based block incomplete LU factorization with CGSTAB acceleration. Numerical tests are carried out using various standard airfoil shapes, at transonic and supersonic conditions. The full Newton, high order Jacobian technique is more robust and efficient than the usual approach. The Jacobian matrices can be readily solved using at least a level (2) block incomplete factorization preconditioner.