Simplified diffusion-convection model w/ Rayleigh-Taylor unstability

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SUMMARY

The discussion focuses on modeling convection in fluids experiencing Rayleigh-Taylor instability, specifically through a one-dimensional approximation. The user seeks to predict concentration distribution over time using velocity vectors related to density gradients, expressed as v = constant * (dc/dx)^n or v = f(mu) * (dc/dx)^n, where mu represents viscosity. The user acknowledges the inherent three-dimensional nature of the problem but aims to derive a simplified model that captures essential dynamics. The essential reference for this topic is Chandrasekhar's "Hydrodynamic and Hydromagnetic Stability," which provides analytical solutions for Rayleigh-Taylor instability.

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  • Understanding of Rayleigh-Taylor instability
  • Familiarity with fluid dynamics principles
  • Knowledge of numerical methods for solving differential equations
  • Basic concepts of viscosity and its role in fluid motion
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  • Study Chandrasekhar's "Hydrodynamic and Hydromagnetic Stability" for analytical solutions
  • Research numerical methods for simulating 2D and 3D fluid dynamics
  • Explore the implications of viscosity on fluid behavior in convection models
  • Investigate existing literature on one-dimensional approximations in fluid dynamics
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Researchers, physicists, and engineers interested in fluid dynamics, particularly those studying convection phenomena and stability in multi-phase systems.

TboneWalker
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I am attempting to make a simple phenomenological model of convection in a fluid with a negative concentration gradient. The heavier fluid overlaying light fluid will under many conditions cause a so called Rayleigh-Taylor unstability, and the denser fluid will move downwards as a result. I've been trying to make a one-dimensional approximation of this effect that can predict concentration distribution over time. My first thought was to have a velocity vector that was in some way related to the density gradient, such as

v = constant * (dc/dx)^n
or
v = f(mu) * (dc/dx)^n
mu: viscosity

Im stuggling to find litterature on this, except for numerical solutions of 2D and 3D problems. My hope was to in some way get an average of 2D and 3D effects respresented in the 1D solution. Any thoughts or helpful advice?
 
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I don't see how you can have a 1-D system where this occurs, since as the (say) heavy fluid falls, the light fluid rises. It's a fundamentally 3D problem.

Chandrasekhar's book "Hydrodynamic and Hydromagentic Stability" is the essential book for this problem. The Rayleigh-Taylor instability is solved analytically in section 10.
 
I know that this convection can not physically happen in one dimension,
I just though it would be possible to approximate a formulation through a 1D equation, that in some way would give us an area-averaged density as a function of height and time...

Thanks for the book tip btw :)
 

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