An Efficient Time-Domain Equivalent Source Method for Acoustic Scattering

The prediction of acoustic scattering from hard surfaces such as the fuselage or deck near an exhausting jet aircraft or rotorcraft is important to attempts at predicting the spatial effects of various engine and nozzle configurations. A time-domain equivalent source method similar to Lee et al.'s method is presented for predicting acoustic scattering using pressure gradient predictions obtained from the G1A formulation. In contrast to Lee's method, the approach proposed here involves using coincident source and control points, leading to improved performance for some geometries. The greatest advantage appears to be for planar surfaces, where interaction between panels is avoided. Validation cases considered include a series of planar segments for analytical validation as well as cases to validate the use of the G1A inputs in connection with the proposed method, and a series of scattering cases using input from an acoustic data surface.