Investigation of the screech-tones excitation by the supersonic jet with laser transillumination method

2016 ◽  
Author(s):  
D. A. Marakasov ◽  
V. M. Sazanovich ◽  
R. Sh. Tsvyk
Keyword(s):  
Supersonic Jet ◽  
Screech Tones

Experimental Investigation on Supersonic Jet Screech Tones

2012 ◽  
Vol 232 ◽  
pp. 213-217
Author(s):  
Jia Ming Li ◽  
Chun Bo Hu ◽  
Jun Hua Bai
Keyword(s):  
Mach Number ◽  
Field Distribution ◽  
Experimental Measurement ◽  
Supersonic Jet ◽  
Jet Noise ◽  
Occurrence Frequency ◽  
Supersonic Jet Noise ◽  
Nozzle Size ◽  
Screech Tones ◽  
Peak Value

In order to investigate the characteristic of the supersonic jet screech tones, an experimental bench of the supersonic jet was designed and a free field noise signal acquisition system was established. Effects of the nozzle size and jet Mach number on jet noise sound field distribution was analyzed, through the result comparison of supersonic jet noise experimental measurement. Results indicate that the field distribution of supersonic jet screech tones is characterized with very strong directivity. Peak value of the screech tones decrease and occurrence frequency of the screech tones increase with the decreasing jet exit Mach number; occurrence frequency of the screech tones decrease with the increasing nozzle size, but the peak value change very less. The experimental measurement of supersonic jet noise provides mechanism research of sound production with data supports and references; and also provides the numerical modeling of supersonic jet noise with validation criteria.

scholarly journals A complex-valued resonance model for axisymmetric screech tones in supersonic jets

2021 ◽  
Vol 928 ◽  
Author(s):  
Matteo Mancinelli ◽  
Vincent Jaunet ◽  
Peter Jordan ◽  
Aaron Towne
Keyword(s):  
Shear Layer ◽  
Travelling Waves ◽  
Finite Thickness ◽  
Supersonic Jet ◽  
Travelling Wave ◽  
Necessary Condition ◽  
Reflection Coefficients ◽  
Resonance Model ◽  
Screech Tones ◽  
Complex Valued

We model the resonance mechanism underpinning generation of A1 and A2 screech tones in an under-expanded supersonic jet. Starting from the resonance model recently proposed by Mancinelli et al. (Exp. Fluids, vol. 60, 2019, p. 22), where the upstream-travelling wave is a neutrally stable guided-jet mode, we here present a more complete linear-stability-based model for screech prediction. We study temperature and shear-layer thickness effects and show that, in order to accurately describe the experimental data, the effect of the finite thickness of the shear layer must be incorporated in the jet-dynamics model. We then present an improved resonance model for screech-frequency predictions in which both downstream- and upstream-travelling waves may have a complex wavenumber and frequency. This resonance model requires knowledge of the reflection coefficients at the upstream and downstream locations of the resonance loop. We explore the effect of the reflection coefficients on the resonance model and propose an approach for their identification. The complex-mode model identifies limited regions of frequency–flow parameter space for which the resonance loop is amplified in time, a necessary condition for the resonance to be sustained. This model provides an improved description of the experimental measurements.

An experimental study of the nozzle lip thickness effect on supersonic jet screech tones

2006 ◽  
Vol 20 (4) ◽  
pp. 522-532 ◽  
Author(s):  
Toshiyuki Aoki ◽  
Yong-Hun Kweon ◽  
Yoshiaki Miyazato ◽  
Heuy-Dong Kim ◽  
Toshiaki Setoguchi
Keyword(s):  
Experimental Study ◽  
Supersonic Jet ◽  
Thickness Effect ◽  
Screech Tones

Investigation on the Source Locations of Axisymmetric Screech Tones Utilizing Data from Numerical Simulation

2019 ◽  
Vol 27 (04) ◽  
pp. 1850058
Author(s):  
Incheol Lee ◽  
Duck Joo Lee
Keyword(s):  
Mach Number ◽  
Fourth Order ◽  
Mixing Layer ◽  
Supersonic Jet ◽  
Shock Cell ◽  
Jet Mixing ◽  
Screech Tone ◽  
Runge Kutta Method ◽  
Cell Structures ◽  
Screech Tones

The source locations of axisymmetric modes of screech tones are numerically investigated. Fourth-order optimized compact scheme and fourth-order Runge–Kutta method are used to solve the 2-D axisymmetric Euler equations. The screech tone is successfully reproduced, and the change in wavelength with respect to jet Mach number shows good agreement with the experimental data. At various low supersonic jet Mach numbers, the time-averaged contours of Mach number and root-mean-square pressure are investigated to identify the location of maximum interaction between shock cell structures and vortices. The source locations of two axisymmetric modes, A1 and A2 modes, are distinctly visualized and identified; the screech tones of A1 mode are generated at the apex of fifth shock cell, and the screech tones of A2 mode are generated at the apex of fourth shock cell. Based on the observation, a simple formula for the prediction of axisymmetric modes of screech tones is proposed. The formula is derived based on a form of Rossiter equation, with the assumption of different convection speeds along the jet mixing layer. The proposed formula successfully estimates the frequency of two axisymmetric modes of screech tones, which verifies that the identified source locations of the axisymmetric screech tones are reasonable.

Supersonic jet spectrometry of chemical species resulting from thermal decomposition of polystyrene and polycarbonate

1992 ◽  
Vol 64 (19) ◽  
pp. 931A-940A ◽  
Author(s):  
Totaro Imasaka ◽  
Masami Hozumi ◽  
Nobuhiko Ishibashi
Keyword(s):  
Thermal Decomposition ◽  
Supersonic Jet ◽  
Chemical Species
Sign in / Sign up

Export Citation Format

Share Document