Bubble Dynamics Model for Hydrodynamically Unstable Interfaces

Several particle methods such as molecular dynamics, lattice gas, lattice Boltzmann and Bird will be compared to Navier–Stokes continuum hydro-dynamics as to their relative advantages and disadvantages. Particularly, the simulation of the " consistent " Boltzmann and its Enskog extension will be discussed. Evolution of the Rayleigh–Taylor unstable interface is known to be domi-nanted by bubble growth and merging processes (1,2). Models that have been developed describe the unstable front as composed of many bubbles (the basic particles) which are rising in the gravitational field (the one–body dynamics) and merging (the two–body dynamics), where larger bubbles absorb smaller bubbles. A new statistical model has been developed(3,4). The new model is based on the Sharp–Wheeler–Glimm models(1), and incorporates the basic feature of single–bubble rise and two–bubble competition using an extended Layzer potential flow model for large density ratio(A = 1) and incompress-ible fluids. The model offers a unified treatment of the Rayleigh–Taylor and the Richtmyer–Meshkov instabilities. The merger model dynamics for both 1