Acoustic sources in a turbulent jet: A direct numerical simulation study

Research output: Contribution to conferencePaperpeer-review

Abstract

A direct numerical simulation of a Mach 0.9, Reynolds number 3600 jet is presented and analyzed. The simulation results are shown to be in excellent agreement with corresponding experiments conducted by Stromberg et al.1 To understand noise mechanisms, Lighthill's theory is used to define a nominal acoustic source which is computed using Fourier methods to provide its streamwise wavenumber and frequency makeup. It is shown that the radiating portion of the source, defined by the sum of its components with supersonic phase velocities, has a significantly different character than the full Lighthill source. Similarly, the turbulent kinetic energy is shown to be poorly correlated with the radiating source. Streamwise phase velocities of the source are found to be distributed fairly evenly between 0.1aand 0.5a, where a is the ambient speed of sound. The “structure” of the radiating source is examined by filtering its non-radiating components. This reveals a simple modulated harmonic wave form as might be predicted by linear instability analysis. A simple model is used to demonstrate that the noise is extremely sensitive to minor disruptions of this form.

Original languageEnglish (US)
DOIs
StatePublished - 1999
Externally publishedYes
EventAeroacoustics Conference and Exhibit, AIAA/CEAS 1999 - Bellevue, United States
Duration: May 10 1999May 12 1999

Other

OtherAeroacoustics Conference and Exhibit, AIAA/CEAS 1999
Country/TerritoryUnited States
CityBellevue
Period5/10/995/12/99

ASJC Scopus subject areas

  • Engineering(all)

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