Discrimination of acoustic and turbulent components from aeroacoustic wall pressure field

Abstract

The investigation of the wall pressure excitations over transportation vehicle panel is of great interest to improve the knowledge of vehicle interior noise transmission and also for future noise reduction strategies. A particularly useful task concerns the characterization and the separation of both acoustic and turbulent components of the wall pressure excitation. A new application of the Proper Orthogonal Decomposition (POD) is tested from two different databases: (i) wall pressure fields synthesized from theoretical average models and (ii) wall pressure fields obtained from Lattice Boltzmann Method numerical simulation. In each case, POD application leads to an energetic partitioning of the wall pressure field that permits to well decouple both acoustic and turbulent fields, especially for mid and high frequencies under interest. To validate such separation and to demonstrate the effectiveness of the POD method, the wavenumber spectrum analysis as well as phase analysis is successively performed. Such a new splitting method provides an instantaneous acoustic-turbulent separation of an inhomogeneous wall pressure field, suggesting many useful future applications.