Ben-Gurion University of the NegevAstrophysics and Cosmology GroupAstrophysics, Relativity, Cosmology, and Space Physics |
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Speaker: Yonatan Elbaz (NCRC/BGU) June 12, 2013 The
effect of initial conditions on Rayleigh-Taylor and Richtmyer-Meshkov
instabilities and the characteristics of their asymptotic self-similar
behavior
The
Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instabilities are
closely related classical hydrodynamic instabilities occurring when a
light fluid accelerates (or supports in a gravitational field) a
heavier fluid. These instabilities arise in many astrophysical
scenarios (such as the expansion of a supernova remnant into the
interstellar medium), as well as in technological systems (most
importantly, in inertial confinement fusion - ICF). The evolution of
multimode initial conditions is usually assumed to involve a
self-similar growth rate independent of the initial conditions.
In this talk, an analysis of the effect of initial conditions on RT and RM instabilities will be presented using a simple nonlinear modal model based on a 2nd order perturbation equation, and the conditions which lead to self-similar growth will be discussed. It will be shown that in many practical applications, RT and RM instabilities do not 'forget' the initial conditions - a fact which has important implications for the analysis and extrapolation of experimental and numerical data. |
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Last updated
by Uri Keshet,
2013 |