Effects of Active Control on the Flow Structure of Flow in a High Reynolds Number Supersonic Jet

2008 ◽  
Author(s):  
Jin-Hwa Kim ◽  
Mo Samimy
Keyword(s):  
Reynolds Number ◽  
Active Control ◽  
Flow Structure ◽  
High Reynolds Number ◽  
Supersonic Jet ◽  
Structure Of Flow ◽  
High Reynolds

Active Control of a High Reynolds Number Mach 0.9 Axisymmetric Jet

AIAA Journal ◽  
2009 ◽  
Vol 47 (1) ◽  
pp. 116-128 ◽  
Author(s):  
J.-H. Kim ◽  
J. Kastner ◽  
M. Samimy
Keyword(s):  
Reynolds Number ◽  
Active Control ◽  
High Reynolds Number ◽  
Axisymmetric Jet ◽  
High Reynolds

Experiments on the instability waves in a supersonic jet and their acoustic radiation

1975 ◽  
Vol 69 (1) ◽  
pp. 73-95 ◽  
Author(s):  
Dennis K. Mclaughlin ◽  
Gerald L. Morrison ◽  
Timothy R. Troutt
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Large Scale ◽  
Acoustic Radiation ◽  
Low Reynolds Number ◽  
Supersonic Jet ◽  
Hot Wire ◽  
Theoretical Predictions ◽  
Low Reynolds ◽  
High Reynolds

An experimental investigation of the instability and the acoustic radiation of the low Reynolds number axisymmetric supersonic jet has been performed. Hot-wire measurements in the flow field and microphone measurements in the acoustic field were obtained from different size jets at Mach numbers of about 2. The Reynolds number ranged from 8000 to 107000, which contrasts with a Reynolds number of 1·3 × 106for similar jets exhausting into atmospheric pressure.Hot-wire measurements indicate that the instability process in the perfectly expanded jet consists of numerous discrete frequency modes around a Strouhal number of 0·18. The waves grow almost exponentially and propagate downstream at a supersonic velocity with respect to the surrounding air. Measurements of the wavelength and wave speed of theSt= 0·18 oscillation agree closely with Tam's theoretical predictions.Microphone measurements have shown that the wavelength, wave orientation and frequency of the acoustic radiation generated by the dominant instability agree with the Mach wave concept. The sound pressure levels measured in the low Reynolds number jet extrapolate to values approaching the noise levels measured by other experimenters in high Reynolds number jets. These measurements provide more evidence that the dominant noise generation mechanism in high Reynolds number jets is the large-scale instability.

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