Wind Noise Modeling in Separated and Reattaching Boundary Layers

The Chase model for the pressure fluctuations in a fully developed turbulent boundary layer is expanded to cover the cases of separated and reattaching boundary layers. Wind tunnel measurements are used to validate the model for flows with positive and negative pressure gradients and flows over discontinuities causing separation. The outer variables of the boundary layer are used to determine a two dimensional surface wavenumber spectrum to be used as an excitation source in an SEA model. The flow over a vehicle is modeled and the predicted panel vibration and interior noise are compared to full scale road test data. The results indicate that the cross spectral densities obtained from pairs of surface mounted microphones are sufficient for determining the wind noise excitation in the SEA model.