A computational approach to flow noise

Abstract

The ability to calculate the noise internal to a structure due to external flow is a necessity for the optimal design of a low noise structure. Whether the structure is an automobile, an airplane or an acoustical array, the goal is the same: to in some way minimize the acoustic pressure/particle velocity resulting from flow excitation at a design location. The excitation is usually that due to wall pressure fluctuations resulting from turbulent boundary layer (TBL). There is a long history of modeling plate excitation due to TBL loads. In most cases, the existing work makes use of statistical, empirically based models for the TBL excitation. This work focuses on combining the capabilities of computational fluid dynamics with computational structural acoustics to enable the calculation of flow noise primarily for undersea vehicles. The work is limited to the non-coupled problem, where the flow calculations are made over a non-deforming boundary with the goal of calculating wall pressure fluctuations and using them as loads on a finite element structural acoustics model. The ultimate goal of this work is to develop the capability to calculate flow noise for three dimensional undersea structures for which analytical approaches are not possible.