Modeling Dissipation Equation in Supersonic Turbulent Mixing Layers with High-Density Gradients

AIAA Journal ◽  
2000 ◽  
Vol 38 (9) ◽  
pp. 1650-1655 ◽  
Author(s):  
Dominique Guezengar ◽  
Herve Guillard ◽  
Jean-Paul Dussauge
Keyword(s):  
Turbulent Mixing ◽  
High Density ◽  
Mixing Layers ◽  
Density Gradients ◽  
Dissipation Equation

Modeling dissipation equation in supersonic turbulent mixing layers with high-density gradients

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 1650-1655 ◽  
Author(s):  
Dominique Guezengar ◽  
Herve Guillard ◽  
Jean-Paul Dussauge
Keyword(s):  
Turbulent Mixing ◽  
High Density ◽  
Mixing Layers ◽  
Density Gradients ◽  
Dissipation Equation

Statistical characteristics of turbulent mixing in spherical and cylindrical converging Richtmyer–Meshkov instabilities

2021 ◽  
Vol 928 ◽  
Author(s):  
Xinliang Li ◽  
Yaowei Fu ◽  
Changping Yu ◽  
Li Li
Keyword(s):  
Turbulent Mixing ◽  
Initial Perturbation ◽  
Great Influence ◽  
Mixing Layers ◽  
Statistical Characteristics ◽  
Computational Domain ◽  
Heavy Fluid ◽  
Node Number ◽  
Geometric Effect ◽  
Atwood Number

In this paper, the Richtmyer–Meshkov instabilities in spherical and cylindrical converging geometries with a Mach number of approximately 1.5 are investigated by using the high resolution implicit large eddy simulation method, and the influence of the geometric effect on the turbulent mixing is investigated. The heavy fluid is sulphur hexafluoride (SF6), and the light fluid is nitrogen (N2). The shock wave converges from the heavy fluid into the light fluid. The Atwood number is 0.678. The total structured and uniform Cartesian grid node number in the main computational domain is 20483. In addition, to avoid the influence of boundary reflection, a sufficiently long sponge layer with 50 non-uniform coarse grids is added for each non-periodic boundary. Present numerical simulations have high and nonlinear initial perturbation levels, which rapidly lead to turbulent mixing in the mixing layers. Firstly, some physical-variable mean profiles, including mass fraction, Taylor Reynolds number, turbulent kinetic energy, enstrophy and helicity, are provided. Second, the mixing characteristics in the spherical and cylindrical turbulent mixing layers are investigated, such as molecular mixing fraction, efficiency Atwood number, turbulent mass-flux velocity and density self-correlation. Then, Reynolds stress and anisotropy are also investigated. Finally, the radial velocity, velocity divergence and enstrophy in the spherical and cylindrical turbulent mixing layers are studied using the method of conditional statistical analysis. Present numerical results show that the geometric effect has a great influence on the converging Richtmyer–Meshkov instability mixing layers.

scholarly journals Coherent vortex simulation of three-dimensional turbulent mixing layers using orthogonal wavelets

2005 ◽  
Vol 534 ◽  
pp. 39-66 ◽  
Author(s):  
KAI SCHNEIDER ◽  
MARIE FARGE ◽  
GIULIO PELLEGRINO ◽  
MICHAEL M. ROGERS
Keyword(s):  
Turbulent Mixing ◽  
Three Dimensional ◽  
Mixing Layers ◽  
Orthogonal Wavelets ◽  
Coherent Vortex

scholarly journals Analysis of one-dimensional models for exchange flows under strong stratification

2019 ◽  
Vol 70 (1) ◽  
pp. 41-56
Author(s):  
Steven J. Kaptein ◽  
Koen J. van de Wal ◽  
Leon P. J. Kamp ◽  
Vincenzo Armenio ◽  
Herman J. H. Clercx ◽  
...  
Keyword(s):  
Density Gradient ◽  
Turbulent Mixing ◽  
Schmidt Number ◽  
Density Gradients ◽  
One Dimensional ◽  
Exchange Flows ◽  
Dimensional Models ◽  
The One ◽  
Horizontal Density Gradient ◽  
Classical Constant

AbstractOne-dimensional models of exchange flows driven by horizontal density gradients are well known for performing poorly in situations with weak turbulent mixing. The main issue with these models is that the horizontal density gradient is usually imposed as a constant, leading to non-physically high stratification known as runaway stratification. Here, we propose two new parametrizations of the horizontal density gradient leading to one-dimensional models able to tackle strongly stratified exchange flows at high and low Schmidt number values. The models are extensively tested against results from laminar two-dimensional simulations and are shown to outperform the models using the classical constant parametrization for the horizontal density gradients. Four different flow regimes are found by exploring the parameter space defined by the gravitational Reynolds number Reg, the Schmidt number Sc, and the aspect ratio of the channel Γ. For small values of RegΓ, when diffusion dominates, all models perform well. However, as RegΓ increases, two clearly distinct regimes emerge depending on the Sc value, with an equally clear distinction of the performance of the one-dimensional models.

The potential flow bounded by a mixing layer and a solid surface

1984 ◽  
Vol 395 (1809) ◽  
pp. 265-290 ◽  
Keyword(s):  
Shear Layer ◽  
Solid Surface ◽  
Turbulent Mixing ◽  
Potential Flow ◽  
Near Field ◽  
Mixing Layer ◽  
Detailed Comparison ◽  
Mixing Layers ◽  
Turbulent Shear ◽  
Spatial Correlations

Phillips's ( Proc. Camb. Phil. Soc . 51, 220 (1955)) analysis of the potential 'near field' forced by a turbulent shear layer is extended to include calculation of velocity spectra, spatial correlations and the effect of a solid surface at a finite distance from the shear layer. In the region away from the influence of the wall the theory predicts that correlation scales depend principally on the effective distance from the turbulence. This result suggests that the large correlation scales measured outside turbulent mixing layers do not necessarily demonstrate the essential tow-dimensionality of the large turbulent eddies and shows why mixing layers are more influenced by potential flow effects than are other shear layers. The detailed comparison of the theory to measurements made outside a high Reynolds number single-stream turbulent mixing layer results in an unphysical negative regions are caused by an error in a basic assumption of the theory. However, all the measured correlation scales appear to increase linearly with distance from the turbulence and therefore are consistent with the main result of the analysis. As the potential flow becomes affected by the wind tunnel floor, u 2 — and w 2 — are amplified significantly more than the theory predicts, while v 2 — is not attenuated. These discrepancies are attributed partly to the streamwise inhomogeneity of the flow, which was not incorporated into the analysis.

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