A method for solving compressible flow equations in an unsteady free stream

The paper presents a method to increase the computational accuracy by preserving additional constraints on the numerical solution. The new technique can noticeably increase the precision of a standard finite-volume flow solver by a modification to the flux computation procedure without changing its essential features. The efficiency of this method is demonstrated by application to the prediction of sound from high-speed helicopter blades. Several open domain boundary conditions for this application are also developed and compared for a model problem of a two-dimensional transonic aerofoil in an unsteady free stream.