Abstract: An algorithm is proposed to combine Kirchhoff integral and an unsteady flow computation. Axisymmetric jet flows are given by DNS using 5-order accurate upwind compact scheme and 3-order accurate Runge-Kutta scheme. Kirchhoff integral is used to predict the far-field sound. Numerical results show that far-field sound pressure has the directivity and reaches maximal value at 20° diverged from the flow direction. The directivity is attenuating while the propagation distance is increasing.

Key words: aeroacoustic noise, axisymmetric jet, Kirchhoff integral, compact difference scheme