TURBULENCE IN SOUND EXCITED JETS

MEASUREMENTS AND THEORY.

Research output: Contribution to journalConference article

2 Citations (Scopus)

Abstract

The mechanisms by which the turbulent structure of an axisymmetric jet is modified by the presence of an acoustic excitation are examined. A model is described in which the excitation triggers instability waves at the jet exit. As these waves propagate downstream they extract energy from the mean flow and transfer it to the random turbulence. This results in an increase of the random turbulence levels and a more rapid mixing and spreading for the jet. It is shown that at high frequencies the presence of the instability wave may reduce the random turbulence levels. Numerical calculations are presented for both the radial and axial variation in the time-averaged properties of the flow as a function of excitation conditions. The calculations are compared with measurements of fluctuating velocity and pressure in a round jet. Reasonable agreement is found between the calculations and the measurements.

Original languageEnglish (US)
JournalAIAA Paper
StatePublished - Jan 1 1981
EventAIAA Pap AIAA Aerosp Sci Meet, 19th - St Louis, MO, USA
Duration: Jan 12 1981Jan 15 1981

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Turbulence
Acoustic waves
Acoustics

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

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title = "TURBULENCE IN SOUND EXCITED JETS: MEASUREMENTS AND THEORY.",
abstract = "The mechanisms by which the turbulent structure of an axisymmetric jet is modified by the presence of an acoustic excitation are examined. A model is described in which the excitation triggers instability waves at the jet exit. As these waves propagate downstream they extract energy from the mean flow and transfer it to the random turbulence. This results in an increase of the random turbulence levels and a more rapid mixing and spreading for the jet. It is shown that at high frequencies the presence of the instability wave may reduce the random turbulence levels. Numerical calculations are presented for both the radial and axial variation in the time-averaged properties of the flow as a function of excitation conditions. The calculations are compared with measurements of fluctuating velocity and pressure in a round jet. Reasonable agreement is found between the calculations and the measurements.",
author = "Morris, {Philip John} and C. Baltas",
year = "1981",
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TURBULENCE IN SOUND EXCITED JETS : MEASUREMENTS AND THEORY. / Morris, Philip John; Baltas, C.

In: AIAA Paper, 01.01.1981.

Research output: Contribution to journalConference article

TY - JOUR

T1 - TURBULENCE IN SOUND EXCITED JETS

T2 - MEASUREMENTS AND THEORY.

AU - Morris, Philip John

AU - Baltas, C.

PY - 1981/1/1

Y1 - 1981/1/1

N2 - The mechanisms by which the turbulent structure of an axisymmetric jet is modified by the presence of an acoustic excitation are examined. A model is described in which the excitation triggers instability waves at the jet exit. As these waves propagate downstream they extract energy from the mean flow and transfer it to the random turbulence. This results in an increase of the random turbulence levels and a more rapid mixing and spreading for the jet. It is shown that at high frequencies the presence of the instability wave may reduce the random turbulence levels. Numerical calculations are presented for both the radial and axial variation in the time-averaged properties of the flow as a function of excitation conditions. The calculations are compared with measurements of fluctuating velocity and pressure in a round jet. Reasonable agreement is found between the calculations and the measurements.

AB - The mechanisms by which the turbulent structure of an axisymmetric jet is modified by the presence of an acoustic excitation are examined. A model is described in which the excitation triggers instability waves at the jet exit. As these waves propagate downstream they extract energy from the mean flow and transfer it to the random turbulence. This results in an increase of the random turbulence levels and a more rapid mixing and spreading for the jet. It is shown that at high frequencies the presence of the instability wave may reduce the random turbulence levels. Numerical calculations are presented for both the radial and axial variation in the time-averaged properties of the flow as a function of excitation conditions. The calculations are compared with measurements of fluctuating velocity and pressure in a round jet. Reasonable agreement is found between the calculations and the measurements.

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