A NEW QUASI ONE-DIMENSIONAL MODEL FOR TURBULENT WAKE MIXING

摘要

A new model for turbulent wake mixing is proposed. The model, which appears supported by laboratory experiments and which is made plausible on physical grounds, considers the wake as consist¬ing of a "marble cake" structure of hot and cold lumps, the cold lumps being mixed into the wake by the large eddies of the turbulent wake. A dynamical (one-dimensional) model for the mixing leads to a simple set of equations which can be numerically integrated to yield the tempera¬ture, density and velocity of the hot and cold wake components. The inclusion of chemistry in the model would yield wake composition. The model permits the prediction of mean square mass and electron density fluctuations. The fluctuations are assumed to arise from random con¬vection of inhomogeneous fluid elements, rather than by compressibility effects or dissipation associated with the turbulent velocity field. The consequences of such mixing for the spectrum of a scalar additive in a wake are qualitatively discussed.