Sound Generation in Compressible Mixing Layers

  • LI Ye
    Department of Mechanical and Aerospace Engineering, Graduate School of Engineering, Tokyo Institute of Technology
  • TANAHASHI Mamoru
    Department of Mechanical and Aerospace Engineering, Graduate School of Engineering, Tokyo Institute of Technology
  • MIYAUCHI Toshio
    Department of Mechanical and Aerospace Engineering, Graduate School of Engineering, Tokyo Institute of Technology

この論文をさがす

抄録

Direct numerical simulations have been performed to clarify the sound generation mechanism in two-dimensional temporally evolving compressible mixing layers. The sound generation in mixing layer is governed by the variations of vorticity which are induced by the Kelvin-Helmholtz instability. The pressure fluctuations with high frequency are observed in the period of vortex roll-up, and the amplitude of pressure fluctuations increase on the occasion of vortex pairing. The acoustic source term is governed by the Reynolds stress component and the viscous component is negligible. The effects of convective Mach number Mc on sound generation are also investigated. Both the pressure fluctuations and acoustic source term increase with the increase of convective Mach number. For Mc=0.6, shock wave called ‘eddy shocklet’ is produced by the vortex pairing, which dominates the sound generation from the mixing layer at high Mc. The far-field sound computed by DNS is compared with the predictions based on the acoustic analogies derived by Powell and Lighthill. The prediction by Powell’s analogy shows a good agreement with DNS, while the pressure fluctuations predicted by Lighthill’s analogy are low compared with the DNS results after the vortex pairing.

収録刊行物

被引用文献 (1)*注記

もっと見る

参考文献 (23)*注記

もっと見る

詳細情報 詳細情報について

問題の指摘

ページトップへ