We present a numerical study of a two dimensional granular medium consisting of hard inelastic disks. The evolution of the medium throughout a cooling process is monitored. Two different types of instabilities (shearing and clustering instability) are found to develop in the system. The development of these instabilities is shown to be in qualitative and quantitative agreement with the predicti...

This chapter summarizes parts of the following textbook and review article: – P. J. Schmid & D. S. Henningson, Stability and Transition in Shear Flows, Springer, 2001. – P. Huerre & M. Rossi, Hydrodynamic instabilities in open flow, in Hydrodynamics and Nonlinear Instabilities, ed. C. Godrèche & P. Manneville, Cambridge University Press, 1998. References to the original bibliography follows the...

Blast-wave-driven hydrodynamic instabilities are studied in the presence of a background B-field through experiments and simulations high-energy-density (HED) physics regime. In conducted at Laboratoire pour l’utilisation des lasers intenses (LULI), laser-driven shock-tube platform was used to generate hydrodynamically unstable interface with prescribed sinusoidal surface perturbation, short-pu...

We propose a hydrodynamic mechanism, based on the Marangoni flow, to describe growth instabilities of liquid-condensed islands in the supercooled liquid-expanded phase of two-dimensional Langmuir monolayers. This Marangoni instability is intrinsic to Langmuir monolayers and is not controlled by the expulsion of chemical impurities from the liquid-condensed phase. The hydrodynamic transport of t...

Beam instabilities in the strongly magnetized electron-positron plasma of pulsar magnetospheres are considered. We analyze the resonance conditions and estimate the growth rates of the Cherenkov and cyclotron instabilities of the ordinary (O), extraordinary (X) and Alfvén modes in two limiting regimes: kinetic and hydrodynamic. As a preliminary step, we reconsider wave dispersion and polarizati...

We propose that the hemispheric asymmetry (Fig. 1) of mare basalts may be explained as a result of hydrodynamic instabilities associated with a layer of mixed ilmenite-rich cumulates (IC) and olivine^orthopyroxene (OPx) overlying a metallic core. This mixed layer (MIC) should form shortly after the solidification of the magma ocean (P.C. Hess and E.M. Parmentier, Earth Planet. Sci. Lett. 134 (1...

Direct numerical simulations of two-dimensional (2D) and three-dimensional (3D), single-mode multi-mode, incompressible immiscible Rayleigh–Taylor (RT) instabilities are performed using a phase-field approach high-order finite-difference schemes. Various combinations Atwood number, Reynolds surface tension, initial perturbation amplitude investigated. It is found that at high numbers, the if si...

When hard plasma disruptions produce melting of a surface layer on first wall components, the melt layer is in general also subject to various forces. Among these, the forces produced by eddy currents and the magnetic fields are the most severe, and they may cause the removal of the melt layer. It appears that one of the most effective mechanisms for removal is by a Rayleigh-Taylor instability....