A PRECONDITIONER FOR STEADY 2-DIMENSIONAL TURBULENT-FLOW SIMULATION

The approximate factorisation-conjugate gradient squared (AF-CGS) meth od has been successfully demonstrated for unsteady turbulent aerofoil flows and transonic inviscid flows in two and three dimensions. The me thod consists of a conjugate gradient solution of the linear system at each step with the ADI approximate factorisation as a preconditioner. In the present paper the method is adapted to obtain rapid convergenc e for steady aerofoil flows when compared to the basic explicit method . Modifications to the original method are described, convergence crit eria are examined and the method is demonstrated for transonic flow in cluding AGARD test case 9 for the RAE2822 aerofoil.