Turbulent boundary layer simulation with an array of loudspeakers

The feasibility is discussed of simulating a random pressure field having the same spatial correlation function as a turbulent boundary-layer pressure field using an array of loudspeakers. This approach could provide a cost-effective laboratory method of measuring the boundary-layer noise transmitted through aircraft fuselage structures. Initially, a theoretical model is used to predict the vibroacoustic response of randomly excited panels. A method of generating a pressure field with predefined statistical properties using an array of loudspeakers is then introduced. Results are obtained in a typical test case for the simulation of boundary-layer-induced noise. It is shown how the number of loudspeakers required to achieve a reasonable approximation of the boundary-layer excitation scales with frequency. It is found that a coarse reproduction of the boundary-layer excitation, using a reduced set of loudspeakers, can still give a good approximation of the panel vibroacoustic response, thus suggesting that direct simulation of the panel response to a boundary-layer excitation using loudspeakers could be feasible.