COMPUTATIONAL CONSIDERATIONS FOR THE SIMULATION OF SHOCK-INDUCED SOUND

The numerical study of aeroacoustic problems places stringent demands on the choice of a computational algorithm because it requires the abi lity to propagate disturbances of small amplitude and short wavelength . The demands are particularly high when shock waves are involved beca use the chosen algorithm must also resolve discontinuities in the solu tion. The extent to which a high-order accurate shock-capturing method can be relied upon for aeroacoustics applications that involve the in teraction of shocks with other waves has not been previously quantifie d. Such a study is initiated in this work. A fourth-order accurate ess entially nonoscillatory (ENO) method is used to investigate the soluti ons of inviscid, compressible flows with shocks. The design order of a ccuracy is achieved in the smooth regions of a steady-state, quasi-one -dimensional test case. However, in an unsteady test case, only first- order results are obtained downstream of a sound-shock interaction. Th e difficulty in obtaining a globally high-order accurate solution in s uch a case with a shock-capturing method is demonstrated through the s tudy of a simplified, linear model problem. Some of the difficult issu es and ramifications for aeroacoustic simulations of flows with shocks that are raised by these results are discussed.