scholarly journals Group theory analysis of early-time scale-dependent dynamics of the Rayleigh-Taylor instability with time varying acceleration

2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Desmond L. Hill ◽  
Aklant K. Bhowmick ◽  
Dan V. Ilyin ◽  
Snezhana I. Abarzhi
Keyword(s):  
Group Theory ◽  
Time Scale ◽  
Early Time ◽  
Taylor Instability ◽  
Time Varying ◽  
Theory Analysis ◽  
Rayleigh Taylor Instability

scholarly journals On the “Early-Time” Evolution of Variables Relevant to Turbulence Models for the Rayleigh-Taylor Instability

2010 ◽  
Author(s):  
Bertrand Rollin ◽  
Malcolm J. Andrews
Keyword(s):  
Turbulence Model ◽  
Initial Conditions ◽  
Mixing Layer ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Early Time ◽  
Variable Density ◽  
Taylor Instability ◽  
Turbulent Regime ◽  
Rayleigh Taylor Instability

We present our progress toward setting initial conditions in variable density turbulence models. In particular, we concentrate our efforts on the BHR turbulence model [1] for turbulent Rayleigh-Taylor instability. Our approach is to predict profiles of relevant variables before fully turbulent regime and use them as initial conditions for the turbulence model. We use an idealized model of mixing between two interpenetrating fluids to define the initial profiles for the turbulence model variables. Velocities and volume fractions used in the idealized mixing model are obtained respectively from a set of ordinary differential equations modeling the growth of the Rayleigh-Taylor instability and from an idealization of the density profile in the mixing layer. A comparison between predicted profiles for the turbulence model variables and profiles of the variables obtained from low Atwood number three dimensional simulations show reasonable agreement.

scholarly journals FULLY 3D RAYLEIGH–TAYLOR INSTABILITY IN A BOUSSINESQ FLUID

2019 ◽  
Vol 61 (3) ◽  
pp. 286-304 ◽  
Author(s):  
S. J. WALTERS ◽  
L. K. FORBES
Keyword(s):  
Numerical Calculation ◽  
Spectral Method ◽  
Large Scale ◽  
Three Dimensional ◽  
Early Time ◽  
Taylor Instability ◽  
3D Geometry ◽  
Linearized Theory ◽  
Rayleigh Taylor Instability ◽  
Boussinesq Fluid

Rayleigh–Taylor instability occurs when a heavier fluid overlies a lighter fluid, and the two seek to exchange positions under the effect of gravity. We present a linearized theory for arbitrary three-dimensional (3D) initial disturbances that grow in time, and calculate the evolution of the interface for early times. A new spectral method is introduced for the fully 3D nonlinear problem in a Boussinesq fluid, where the interface between the light and heavy fluids is approximated with a smooth but rapid density change in the fluid. The results of large-scale numerical calculation are presented in fully 3D geometry, and compared and contrasted with the early-time linearized theory.

scholarly journals Fully 3D Rayleigh-Taylor instability in a Boussinesq fluid

2019 ◽  
Vol 61 ◽  
pp. 286-304
Author(s):  
Stephen John Walters ◽  
Lawrence K. Forbes
Keyword(s):  
Numerical Calculation ◽  
Spectral Method ◽  
Large Scale ◽  
Three Dimensional ◽  
Early Time ◽  
Taylor Instability ◽  
3D Geometry ◽  
Linearized Theory ◽  
Rayleigh Taylor Instability ◽  
Boussinesq Fluid

Rayleigh–Taylor instability occurs when a heavier fluid overlies a lighter fluid, and the two seek to exchange positions under the effect of gravity. We present a linearized theory for arbitrary three-dimensional (3D) initial disturbances that grow in time, and calculate the evolution of the interface for early times. A new spectral method is introduced for the fully 3D nonlinear problem in a Boussinesq fluid, where the interface between the light and heavy fluids is approximated with a smooth but rapid density change in the fluid. The results of large-scale numerical calculation are presented in fully 3D geometry, and compared and contrasted with the early-time linearized theory. doi:10.1017/S1446181119000087

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