Crackle - A dominant component of supersonic jet mixing noise

2000 ◽  
Author(s):  
A. Krothapalli ◽  
L. Venkatakrishnan ◽  
L. Lourenco
Keyword(s):  
Supersonic Jet ◽  
Jet Mixing ◽  
Dominant Component ◽  
Mixing Noise

Computation of supersonic jet mixing noise for an axisymmetric convergent-divergent nozzle

1994 ◽  
Vol 31 (3) ◽  
pp. 603-609 ◽  
Author(s):  
Abbas Khavaran ◽  
Eugene A. Krejsa ◽  
Chan M. Kim
Keyword(s):  
Supersonic Jet ◽  
Jet Mixing ◽  
Mixing Noise

Computation of jet mixing noise due to coherent structures: the plane jet case

1997 ◽  
Vol 335 ◽  
pp. 261-304 ◽  
Author(s):  
F. BASTIN ◽  
P. LAFON ◽  
S. CANDEL
Keyword(s):  
Coherent Structures ◽  
Large Scale ◽  
Supersonic Jet ◽  
Low Frequency ◽  
Coherent Motion ◽  
Mean Flow ◽  
Jet Mixing ◽  
Deterministic Modelling ◽  
Plane Jets ◽  
Mixing Noise

A computational approach to the prediction of jet mixing noise is described. It is based on Lighthill's analogy, used together with a semi-deterministic modelling of turbulence (SDM), where only the large-scale coherent motion is evaluated. The features of SDM are briefly illustrated in the case of shear layers, showing that suitable descriptions of the mean flow and of the large-scale fluctuations are obtained. Aerodynamic calculations of two cold fully expanded plane jets at Mach numbers 0.50 and 1.33 are then carried out. The numerical implementation of Lighthill's analogy is described and different integral formulations are compared for the two jets. It is shown that the one expressed in a space–time conjugate (κ, ω)-plane is particularly convenient and allows a simple geometrical interpretation of the computations. Acoustic results obtained with this formulation are compared to relevant experimental data. It is concluded that the radiation of subsonic jets cannot be explained only by the contribution of the turbulent coherent motion. In this case, directivity effects are well recovered but the acoustic spectra are too narrow and limited to the low-frequency range. In contrast at Mach number 1.33, especially in the forward quadrant, results are satisfactory, showing that coherent structures indeed provide the main source of supersonic jet mixing noise.

Significance of shock structure on supersonic jet mixing noise of axisymmetric nozzles

AIAA Journal ◽  
1994 ◽  
Vol 32 (9) ◽  
pp. 1920-1923 ◽  
Author(s):  
Chan M. Kim ◽  
Eugene A. Krejsa ◽  
Abbas Khavaran
Keyword(s):  
Supersonic Jet ◽  
Shock Structure ◽  
Jet Mixing ◽  
Mixing Noise

Experimental investigation of the turbulent density – Far-field sound correlations in compressible jets

2018 ◽  
Vol 17 (4-5) ◽  
pp. 521-540 ◽  
Author(s):  
Bertrand Mercier ◽  
Thomas Castelain ◽  
Christophe Bailly
Keyword(s):  
High Speed ◽  
Rayleigh Scattering ◽  
Photon Counting ◽  
Supersonic Jet ◽  
Density Fluctuations ◽  
Far Field ◽  
Noise Emission ◽  
Jet Mixing ◽  
Cross Correlations ◽  
Mixing Noise

Jet mixing noise is experimentally investigated by means of cross-correlations between density fluctuations inside the turbulent jet flow and the far-field acoustic pressure. The time-resolved density fluctuations are measured by an experimental device based on Rayleigh scattering, which is mounted in the large anechoic wind tunnel of Ecole Centrale de Lyon. An original signal processing developed in a previous study is implemented for the photon counting, combined with the use of a single photomultiplier to remove shot noise. A high-speed subsonic jet and a perfectly expanded supersonic jet with a subsonic convective velocity are considered to characterize mixing noise sources. In order to go beyond the classical Fourier analyses, conditional cross-correlations are determined, and the signature of turbulent events linked to the noise emission in the downstream direction is extracted.

Effects of forward flight on jet mixing noise from fine-scale turbulence

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 1261-1269 ◽  
Author(s):  
Christopher K. W. Tam ◽  
Nikolai Pastouchenko ◽  
Laurent Auriault
Keyword(s):  
Fine Scale ◽  
Forward Flight ◽  
Jet Mixing ◽  
Mixing Noise ◽  
Scale Turbulence

scholarly journals Aspect Ratio Driven Relationship between Nozzle Internal Flow and Supersonic Jet Mixing

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 78
Author(s):  
Kalyani Bhide ◽  
Kiran Siddappaji ◽  
Shaaban Abdallah
Keyword(s):  
Boundary Layer ◽  
Aspect Ratio ◽  
Nozzle Exit ◽  
Supersonic Jet ◽  
Internal Flow ◽  
Shear Stresses ◽  
Loss Mechanism ◽  
Potential Core ◽  
Jet Mixing ◽  
Aspect Ratios

This work attempts to connect internal flow to the exit flow and supersonic jet mixing in rectangular nozzles with low to high aspect ratios (AR). A series of low and high aspect ratio rectangular nozzles (design Mach number = 1.5) with sharp throats are numerically investigated using steady state Reynolds-averaged Navier−Stokes (RANS) computational fluid dynamics (CFD) with k-omega shear stress transport (SST) turbulence model. The numerical shadowgraph reveals stronger shocks at low ARs which become weaker with increasing AR due to less flow turning at the throat. Stronger shocks cause more aggressive gradients in the boundary layer resulting in higher wall shear stresses at the throat for low ARs. The boundary layer becomes thick at low ARs creating more aerodynamic blockage. The boundary layer exiting the nozzle transforms into a shear layer and grows thicker in the high AR nozzle with a smaller potential core length. The variation in the boundary layer growth on the minor and major axis is explained and its growth downstream the throat has a significant role in nozzle exit flow characteristics. The loss mechanism throughout the flow is shown as the entropy generated due to viscous dissipation and accounts for supersonic jet mixing. Axis switching phenomenon is also addressed by analyzing the streamwise vorticity fields at various locations downstream from the nozzle exit.

The effects of forward flight on jet mixing noise from fine scale turbulence

2000 ◽  
Author(s):  
Christopher Tam ◽  
Nikolai Pastouchenko ◽  
Laurent Auriault
Keyword(s):  
Fine Scale ◽  
Forward Flight ◽  
Jet Mixing ◽  
Mixing Noise ◽  
Scale Turbulence
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