Vortex-merger statistical-mechanics model for the late time self-similar evolution of the Kelvin–Helmholtz instability

2003 ◽  
Vol 15 (12) ◽  
pp. 3776-3785 ◽  
Author(s):  
A. Rikanati ◽  
U. Alon ◽  
D. Shvarts
Keyword(s):  
Statistical Mechanics ◽  
Late Time ◽  
Helmholtz Instability ◽  
Mechanics Model ◽  
Self Similar ◽  
Vortex Merger

scholarly journals Observation of dual-mode, Kelvin-Helmholtz instability vortex merger in a compressible flow

2017 ◽  
Vol 24 (5) ◽  
pp. 055705 ◽  
Author(s):  
W. C. Wan ◽  
G. Malamud ◽  
A. Shimony ◽  
C. A. Di Stefano ◽  
M. R. Trantham ◽  
...  
Keyword(s):  
Compressible Flow ◽  
Helmholtz Instability ◽  
Dual Mode ◽  
Vortex Merger

scholarly journals Statistical Mechanics Model for Protein Folding

2009 ◽  
Author(s):  
Alexander Yakubovich ◽  
Andrey V. Solov’yov ◽  
Walter Greiner ◽  
Andrey Solov́yov ◽  
Eugene Surdutovich
Keyword(s):  
Protein Folding ◽  
Statistical Mechanics ◽  
Mechanics Model

scholarly journals A general buoyancy–drag model for the evolution of the Rayleigh–Taylor and Richtmyer–Meshkov instabilities

2003 ◽  
Vol 21 (3) ◽  
pp. 347-353 ◽  
Author(s):  
YAIR SREBRO ◽  
YONI ELBAZ ◽  
OREN SADOT ◽  
LIOR ARAZI ◽  
DOV SHVARTS
Keyword(s):  
Temporal Evolution ◽  
Random Noise ◽  
Single Mode ◽  
Time Dependent ◽  
Late Time ◽  
Random Perturbations ◽  
Linear Stage ◽  
Drag Model ◽  
Characteristic Wavelength ◽  
Self Similar

The growth of a single-mode perturbation is described by a buoyancy–drag equation, which describes all instability stages (linear, nonlinear and asymptotic) at time-dependent Atwood number and acceleration profile. The evolution of a multimode spectrum of perturbations from a short wavelength random noise is described using a single characteristic wavelength. The temporal evolution of this wavelength allows the description of both the linear stage and the late time self-similar behavior. Model results are compared to full two-dimensional numerical simulations and shock-tube experiments of random perturbations, studying the various stages of the evolution. Extensions to the model for more complicated flows are suggested.

scholarly journals Early Time Modifications to the Buoyancy-Drag Model for Richtmyer–Meshkov Mixing

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
David L. Youngs ◽  
Ben Thornber
Keyword(s):  
Initial Conditions ◽  
Mean Field ◽  
Early Time ◽  
Growth Exponent ◽  
Late Time ◽  
Time Behavior ◽  
Mixing Zone ◽  
Drag Model ◽  
Model Based ◽  
Self Similar

Abstract The Buoyancy-Drag model is a simple model, based on ordinary differential equations, for estimating the growth in the width of a turbulent mixing zone at an interface between fluids of different densities due to Richtmyer–Meshkov and Rayleigh–Taylor instabilities. The model is calibrated to give the required self-similar behavior for mixing in simple situations. However, the early stages of the mixing process are very dependent on the initial conditions and modifications to the Buoyancy-Drag model are then needed to obtain correct results. In a recent paper, Thornber et al. (2017, “Late-Time Growth Rate, Mixing, and Anisotropy in the Multimode Narrowband Richtmyer–Meshkov Instability: The θ-Group Collaboration,” Phys. Fluids, 29, p. 105107), a range of three-dimensional simulation techniques was used to calculate the evolution of the mixing zone integral width due to single-shock Richtmyer–Meshkov mixing from narrowband initial random perturbations. Further analysis of the results of these simulations gives greater insight into the transition from the initial linear behavior to late-time self-similar mixing and provides a way of modifying the Buoyancy-Drag model to treat the initial conditions accurately. Higher-resolution simulations are used to calculate the early time behavior more accurately and compare with a multimode model based on the impulsive linear theory. The analysis of the iLES data also gives a new method for estimating the growth exponent, θ (mixing zone width ∼ tθ), which is suitable for simulations which do not fully reach the self-similar state. The estimates of θ are consistent with the theoretical model of Elbaz and Shvarts (2018, “Modal Model Mean Field Self-Similar Solutions to the Asymptotic Evolution of Rayleigh-Taylor and Richtmyer-Meshkov Instabilities and Its Dependence on the Initial Conditions,” Phys. Plasmas, 25, p. 062126).

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