LAUSR

The prediction of near field acoustic velocity is necessary when using equivalent source method and evaluating multi acoustic fields problem. According to the idea of acoustic analogy, this paper induces a vector wave equation of aeroacoustics by rearranging the conservation equations of mass and momentum with a permeable surface. Then, an analytical formulation of the acoustic velocity, called formulation V2A, is derived for sources in a quiescent medium by solving the vector wave equation with the free-space Green’s function. The validity of the formulation is confirmed by numerical results for a stationary monopole, a stationary dipole source, and a rotating monopole source in a quiescent medium. The result indicates that the predication of formulation V2A is nearly identical to the exact solutions no matter in far-field or near-field.