VIBRATION AND NOISE GENERATION BY ELASTIC ELEMENTS EXCITED BY A TURBULENT FLOW

摘要

Vibration and sound generation by elastic structural elements (membrane, strip and plate) of streamlined surfaces excited by low Mach number turbulent flow is considered. The models of Corcos, Chase, Ffowcs Williams and Smol'yakov-Tkachenko for the wavenumber-frequency spectrum of the wall pressure field beneath a turbulent boundary layer are used to describe random excitation. A comparative analysis of the models is carried out. The Chase and Smol'yakov-Tkachenko models are shown to have the best agreement with the Martin and Leehey experimental data. The differences in the predictions of sound fields of turbulence excited elastic elements for all the above models are demonstrated and analyzed. The rules of the acoustic, low wavenumber, and convective wall pressure components are studied. The convective components are shown to make a significant contribution to the vibration and acoustic fields produced by turbulence. The ranges of parameters of the flow and the elastic structure are found (away from structural resonances) where the differences between the wall pressure models are not important for predictions of the sound radiated. At the same time these differences are important when the sound field is estimated near structural resonances. (C) 1997 Academic Press Limited. [References: 24]