The late-time dynamics of the single-mode Rayleigh-Taylor instability

2012 ◽  
Vol 24 (7) ◽  
pp. 074107 ◽  
Author(s):  
P. Ramaprabhu ◽  
Guy Dimonte ◽  
P. Woodward ◽  
C. Fryer ◽  
G. Rockefeller ◽  
...  
Keyword(s):  
Single Mode ◽  
Taylor Instability ◽  
Late Time ◽  
Time Dynamics ◽  
Rayleigh Taylor Instability

scholarly journals Rarefaction-driven Rayleigh–Taylor instability. Part 2. Experiments and simulations in the nonlinear regime

2018 ◽  
Vol 838 ◽  
pp. 320-355 ◽  
Author(s):  
R. V. Morgan ◽  
W. H. Cabot ◽  
J. A. Greenough ◽  
J. W. Jacobs
Keyword(s):  
Rarefaction Wave ◽  
Three Dimensional ◽  
Single Mode ◽  
Taylor Instability ◽  
Nonlinear Regime ◽  
Diffuse Interface ◽  
Late Time ◽  
Two Dimensional ◽  
Rayleigh Taylor Instability ◽  
Atwood Number

Experiments and large eddy simulation (LES) were performed to study the development of the Rayleigh–Taylor instability into the saturated, nonlinear regime, produced between two gases accelerated by a rarefaction wave. Single-mode two-dimensional, and single-mode three-dimensional initial perturbations were introduced on the diffuse interface between the two gases prior to acceleration. The rarefaction wave imparts a non-constant acceleration, and a time decreasing Atwood number, $A=(\unicode[STIX]{x1D70C}_{2}-\unicode[STIX]{x1D70C}_{1})/(\unicode[STIX]{x1D70C}_{2}+\unicode[STIX]{x1D70C}_{1})$, where $\unicode[STIX]{x1D70C}_{2}$ and $\unicode[STIX]{x1D70C}_{1}$ are the densities of the heavy and light gas, respectively. Experiments and simulations are presented for initial Atwood numbers of $A=0.49$, $A=0.63$, $A=0.82$ and $A=0.94$. Nominally two-dimensional (2-D) experiments (initiated with nearly 2-D perturbations) and 2-D simulations are observed to approach an intermediate-time velocity plateau that is in disagreement with the late-time velocity obtained from the incompressible model of Goncharov (Phys. Rev. Lett., vol. 88, 2002, 134502). Reacceleration from an intermediate velocity is observed for 2-D bubbles in large wavenumber, $k=2\unicode[STIX]{x03C0}/\unicode[STIX]{x1D706}=0.247~\text{mm}^{-1}$, experiments and simulations, where $\unicode[STIX]{x1D706}$ is the wavelength of the initial perturbation. At moderate Atwood numbers, the bubble and spike velocities approach larger values than those predicted by Goncharov’s model. These late-time velocity trends are predicted well by numerical simulations using the LLNL Miranda code, and by the 2009 model of Mikaelian (Phys. Fluids., vol. 21, 2009, 024103) that extends Layzer type models to variable acceleration and density. Large Atwood number experiments show a delayed roll up, and exhibit a free-fall like behaviour. Finally, experiments initiated with three-dimensional perturbations tend to agree better with models and a simulation using the LLNL Ares code initiated with an axisymmetric rather than Cartesian symmetry.

scholarly journals Rayleigh-Taylor Instability: A Status Review of Experimental Designs and Measurement Diagnostics

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Arindam Banerjee
Keyword(s):  
Initial Conditions ◽  
Nonlinear Models ◽  
Imaging Techniques ◽  
Mixing Layer ◽  
Single Mode ◽  
Taylor Instability ◽  
Experimental Designs ◽  
Late Time ◽  
Buoyancy Driven Flows ◽  
Rayleigh Taylor Instability

Abstract The focus of experiments and the sophistication of diagnostics employed in Rayleigh-Taylor instability (RTI) induced mixing studies have evolved considerably over the past seven decades. The first theoretical analysis by Taylor and the two-dimensional experimental results by Lewis on RTI in 1950 examined single-mode RTI using conventional imaging techniques. Over the next 70 years, several experimental designs have been used to creating an RTI unstable interface between two materials of different densities. These early experiments though innovative, were arduous to diagnose and provided little information on the internal, turbulent structure and initial conditions of the RT mixing layer. Coupled with the availability of high-fidelity diagnostics, the experiments designed and developed in the last three decades allow detailed measurements of various turbulence statistics that have allowed broadly to validate and verify late-time nonlinear models and mix-models for buoyancy-driven flows. Besides, they have provided valuable insights to solve several long-standing disagreements in the field. This review serves as an opportunity to discuss the understanding of the RTI problem and highlight valuable insights gained into the RTI driven mixing process with a focus on low to high Atwood number (>0.1) experiments.

scholarly journals Revisiting the late-time growth of single-mode Rayleigh–Taylor instability and the role of vorticity

2020 ◽  
Vol 403 ◽  
pp. 132250 ◽  
Author(s):  
Xin Bian ◽  
Hussein Aluie ◽  
Dongxiao Zhao ◽  
Huasen Zhang ◽  
Daniel Livescu
Keyword(s):  
Single Mode ◽  
Taylor Instability ◽  
Late Time ◽  
Rayleigh Taylor Instability

scholarly journals Pure single-mode Rayleigh-Taylor instability for arbitrary Atwood numbers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Wanhai Liu ◽  
Xiang Wang ◽  
Xingxia Liu ◽  
Changping Yu ◽  
Ming Fang ◽  
...  
Keyword(s):  
Single Mode ◽  
Taylor Instability ◽  
Rayleigh Taylor Instability
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