Fully 3D Rayleigh-Taylor instability in a Boussinesq fluid


  • Stephen John Walters University of Tasmania
  • Lawrence K. Forbes University of Tasmania




viscous flow, Rayleigh-Taylor instability, linearization, spectral method.


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

Author Biographies

Stephen John Walters, University of Tasmania

Researcher, School of Mathematics and Physics, University of Tasmania,Hobart, 7001, Tasmania.

Lawrence K. Forbes, University of Tasmania

Professor, School of Mathematics and Physics, University of Tasmania, Hobart, 7001, Tasmania.





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