TY - JOUR
T1 - Application of monotone integrated large eddy simulation to Rayleigh–Taylor mixing
JF - Philosophical Transactions of the Royal Society A: Mathematical,
Physical and Engineering Sciences
JO - Philos Transact A Math Phys Eng Sci
SP - 2971
LP - 2983
M3 - 10.1098/rsta.2008.0303
VL - 367
IS - 1899
AU - Youngs, David L.
Y1 - 2009/07/28
UR - http://rsta.royalsocietypublishing.org/content/367/1899/2971.abstract
N2 - Rayleigh–Taylor (RT) instability occurs when a dense fluid rests on top of a light fluid in a gravitational field. It also occurs in an equivalent situation (in the absence of gravity) when an interface between fluids of different density is accelerated by a pressure gradient, e.g. in inertial confinement fusion implosions. Engineering models (Reynolds-averaged Navier–Stokes models) are needed to represent the effect of mixing in complex applications. However, large eddy simulation (LES) currently makes an essential contribution to understanding the mixing process and calibration or validation of the engineering models. In this paper, three cases are used to illustrate the current role of LES: (i) mixing at a plane boundary, (ii) break-up of a layer of dense fluid due to RT instability, and (iii) mixing in a simple spherical implosion. A monotone integrated LES approach is preferred because of the need to treat discontinuities in the flow, i.e. the initial density discontinuities or shock waves. Of particular interest is the influence of initial conditions and how this needs to be allowed for in engineering modelling. It is argued that loss of memory of the initial conditions is unlikely to occur in practical applications.
ER -