Abstract:

Computational aeroacoustics involves the direct simulation of noise production and radiation from unsteady flows. Its application to problems of practical interest has depended on both algorithm development and advances in computer technology. This paper presents some recent computational aeroacoustics calculations in several different areas. In each case parallel computations are performed to improve efficiency. A new methodology for the numerical simulation of high-speed jet noise is described. It is based on a separation of the instantaneous flow variables into time-averaged and disturbance components. The disturbances are obtained from a three-dimensional, time-dependent, compressible flow simulation. Results are presented for the effects of Mach number and temperature on jet noise. In the simulation of broadband noise from rotors and propellers, a key component is the noise generated by the interaction of a vortical gust with an airfoil. Simulations are described for such an interaction including studies of the effect of airfoil shape and loading. Finally, some examples of the simulation of acoustic scattering in both two and three dimensions from complex geometry bodies in nonuniform flow are described. A discussion of the choice of algorithms, including discretization, boundary treatments, artificial dissipation, and steady-state computations, is provided. [Work supported by NASA.]