Numerical study of supersonic jet and instability wave

Modeling supersonic jet screech. I - Vortical instability wave modeling

10.2514/6.1995-506 ◽

1995 ◽

Cited By ~ 4

Author(s):

Alan Cain ◽

William Bower ◽

Steven Walker ◽

Mary Lockwood

Keyword(s):

Supersonic Jet ◽

Instability Wave ◽

Wave Modeling

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Numerical Study of Shock-Associated Noise in Axisymmetric Supersonic Jet

Fluid-Structure-Sound Interactions and Control - Lecture Notes in Mechanical Engineering ◽

10.1007/978-981-10-7542-1_53 ◽

2018 ◽

pp. 351-357

Author(s):

H. Li ◽

Y. Luo ◽

S. H. Zhang

Keyword(s):

Numerical Study ◽

Supersonic Jet

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Flow Stucture of Supersonic Underexpanded Jet With Microjets Injection

Siberian Journal of Physics ◽

10.54362/1818-7919-2013-8-1-44-55 ◽

2013 ◽

Vol 8 (1) ◽

pp. 44-55

Author(s):

Dmitriy Gubanov ◽

Valeriy Zapryagaev ◽

Nikolay Kiselev

Keyword(s):

Flow Structure ◽

Numerical Study ◽

Mixing Layer ◽

Supersonic Jet ◽

Wave Structure ◽

Streamwise Vortices ◽

Jet Mixing ◽

Underexpanded Jet ◽

Supersonic Underexpanded Jet ◽

The Impact

Experimental and numerical study of transversal microjets injection influence on the supersonic underexpanded jet flow structure has been performed. Data of measurements and calculation have acceptable agreement. Interaction of microjets with main supersonic jet sets to a decrease of an initial gasdynamic region. Microjets lead to a longitudinal streamwise vortices generation and a mushroom-like flow structures create on an external jet mixing layer. Dissipation of longitudinal streamwise vortices was observed at the second jet cell. Complex gasdynamic flow structure of the supersonic underexpanded jet interacting with supersonic microjets has been studied for the first time. This structure contains system of complex chock waves and expansion waves spreading from the position of the impact microjets/main jet localization place. Future of interaction process a chock-wave structure of main jet with additional shock waves has been studied

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Numerical study of the ejection properties of a jet flowing into flooded space

Engineering Journal Science and Innovation ◽

10.18698/2308-6033-2020-2-1955 ◽

2020 ◽

Author(s):

A.Yu. Lutsenko ◽

V.A. Kriushin

Keyword(s):

Pressure Distribution ◽

Nozzle Exit ◽

Software Package ◽

Numerical Study ◽

Supersonic Jet ◽

Underlying Surface ◽

Ansys Fluent ◽

Fluent Software ◽

Underexpanded Supersonic Jet ◽

Jet Axis

The purpose of the study was to carry out a numerical simulation of the interaction of an underexpanded supersonic jet flowing into a flooded space with a normally located obstacle, and with the underlying surface. We performed the calculations in the ANSYS Fluent software package and presented flow patterns. For the case when the obstacle is located normally to the axis of the jet, we compared the pressure distribution in the radial direction with experimental data and made a conclusion about the changes in the integral load on the wall with a change in the distance to the nozzle exit. For the case when the obstacle is parallel to the jet axis, we presented the pressure distribution along the wall in the plane of symmetry, estimated the relative net force acting on the underlying surface, analyzed the nature of its change at various values of the off-design coefficient, the Mach number on the nozzle exit and the distance to the jet axis.

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A numerical study of three-dimensional vortex ring instabilities: viscous corrections and early nonlinear stage

Journal of Fluid Mechanics ◽

10.1017/s0022112094003939 ◽

1994 ◽

Vol 279 ◽

pp. 351-375 ◽

Cited By ~ 48

Author(s):

Karim Shariff ◽

Roberto Verzicco ◽

Paolo Orlandi

Keyword(s):

Growth Rates ◽

Numerical Study ◽

Initial Perturbation ◽

Three Dimensional ◽

Instability Wave ◽

Mean Flow ◽

Hairpin Vortices ◽

Single Wave ◽

Second Mode ◽

Radial Structure

Finite-difference calculations with random and single-mode perturbations are used to study the three-dimensional instability of vortex rings. The basis of current understanding of the subject consists of a heuristic inviscid model (Widnall, Bliss & Tsai 1974) and a rigorous theory which predicts growth rates for thin-core uniform vorticity rings (Widnall & Tsai 1977). At sufficiently high Reynolds numbers the results correspond qualitatively to those predicted by the heuristic model: multiple bands of wavenumbers are amplified, each band having a distinct radial structure. However, a viscous correction factor to the peak inviscid growth rate is found. It is well described by the first term, 1 – α1(β)/Res, for a large range of Res. Here Res is the Reynolds number defined by Saffman (1978), which involves the curvature-induced strain rate. It is found to be the appropriate choice since then α1(β) varies weakly with core thickness β. The three most nonlinearly amplified modes are a mean azimuthal velocity in the form of opposing streams, an n = 1 mode (n is the azimuthal wavenumber) which arises from the interaction of two second-mode bending waves and the harmonic of the primary second mode. When a single wave is excited, higher harmonics begin to grow successively later with nonlinear growth rates proportional to n. The modified mean flow has a doubly peaked azimuthal vorticity. Since the curvature-induced strain is not exactly stagnation-point flow there is a preference for elongation towards the rear of the ring: the outer structure of the instability wave forms a long wake consisting of n hairpin vortices whose waviness is phase shifted π/n relative to the waviness in the core. Whereas the most amplified linear mode has three radial layers of structure, higher radial modes having more layers of radial structure (hairpins piled upon hairpins) are excited when the initial perturbation is large, reminiscent of visualization experiments on the formation of a turbulent ring at the generator.

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Physics and Prediction of Supersonic Jet Noise

Applied Mechanics Reviews ◽

10.1115/1.3124402 ◽

1994 ◽

Vol 47 (6S) ◽

pp. S184-S187

Author(s):

Christopher K. W. Tam

Keyword(s):

Supersonic Jet ◽

Jet Noise ◽

Supersonic Jets ◽

Wave Radiation ◽

Instability Wave ◽

Empirical Constant ◽

Supersonic Jet Noise ◽

Turbulence Structures ◽

Mixing Noise ◽

Dominant Part

Both the large turbulence structures and the fine scale turbulence of the flows of supersonic jets are sources of turbulent mixing noise. At moderately high supersonic Mach numbers especially for hot jets, the dominant part of the noise is generated directly by the large turbulence structures. The large turbulence structures propagate downstream at supersonic velocities relative to the ambient sound speed. They generate strong Mach wave radiation analogous to a supersonically travelling wavy wall. A stochastic instability wave model theory of the large turbulence structures and noise of supersonic jets has recently been developed. The theory can predict both the spectrum and directivity of the dominant part of supersonic jet noise up to a multiplicative empirical constant. Calculated results agree well with measurements.

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