Computation of Broadband Mixing Noise from Turbomachinery

Abstract

Time dependent CFD solutions are often contaminated by parasite waves. These waves consist of high frequency grid to grid oscillations. They are known to propagate with unusually high speed. The parasite waves are extremely undesirable creations of finite difference schemes. They degrade the quality of the solution. They introduce spurious nonlinear effects into the computed solutions. During the last six months we initiated and carried out a study of these waves. The scope of the study covers the generation of these waves and their propagation characteristics. Most important of all we have developed a way to selectively damp out these waves without affecting the main wave components. The effectiveness of the selective damping is demonstrated by a number of examples including wave solutions with discontinuities.

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Document Details

Document Type
Technical Report
Publication Date
Feb 29, 1992
Accession Number
ADA251605

Entities

People

  • Christopher Tam

Organizations

  • Florida State University

Tags

DTIC Thesaurus Topics

  • Acoustics
  • Aeroacoustics
  • Anisotropy
  • Broadband
  • Computational Fluid Dynamics
  • Computational Science
  • Computations
  • Dispersion Relations
  • Equations
  • Frequency
  • Helmholtz Equations
  • Mathematics
  • Military Research
  • Noise
  • Parasites
  • Physics
  • Propeller Noise

Readers

  • Computational Fluid Dynamics (CFD)
  • Immunology
  • Microwave Engineering.