Vibroacoustics of panels subjected to turbulent boundary layer excitation with pressure gradients

Current research advancement in aircraft engine technology with significant noise reduction at the source (i.e. engine) has created renewed interest in turbulent boundary layer (TBL) generated cabin noise in aircraft. The recent studies using computational fluid dynamics (CFD) and wind tunnel tests are focused on getting the reliable spectra of TBL excitation in areas of aircraft with favorable pressure gradient (FPG) and adverse pressure gradient (APG), respectively. The aim of this paper is to increase the understanding of TBL excitation with adverse pressure gradients and quantify their impact on sound radiation from aircraft stiffened panels subjected to TBL excitation with such pressure gradients. Based on literature review, it is found that most of the developed models for TBL auto-spectra under pressure gradients fit quite well to the wind tunnel tests which are used to develop these models. However, recently proposed Rozenberg model seems to perform well when compared to different set of data obtained either by wind tunnel tests or obtained through numerical simulations using CFD. Therefore, this Rozenberg model is used to perform vibroacoustic studies addressed in this paper. For a reference case, Goody's TBL model for zero pressure gradients is also discussed.