BUDGET OF EQUATIONS FOR REYNOLDS STRESSES IN A TURBULENT PATCH ARISING FROM INTERNAL WAVE BREAKING

Results of the direct numerical simulations are used to obtain statistical moments in a quasi-steady turbulent patch arising in a stably stratified flow above an obstacle after internal wave breaking. Temporal evolution and spatial behavior of the Reynolds-stress tensor components and budgets of the Reynolds-stress transport equations have been studied. Such an analysis is helpful to explore the turbulent patch and its energetic characteristics by means of statistical moments, to examine closure hypotheses in turbulence models, and to evaluate geophysically important quantites. In particular, the calculated global value of the mixing efficiency is about 0.2 as in oceanic applications. Moreover, simple algebraic relations are proposed between the turbulent kinetic energy and its dissipation rate. In the Reynolds stress tensor equation, the pressure-strain correlation term provides the redistribution of the normal stress components according to the linear returnto-isotropy approximation, whereas the dissipation tensor roughly follows the local-isotropy assumption.

Keywords:
stable stratification, internal wave breaking, flow above obstacle, direct numerical simulation, turbulence models, statisitical moments, turbulent kinetic energy.
УДК 532.517.4

BUDGET OF EQUATIONS FOR REYNOLDS STRESSES IN A TURBULENT PATCH ARISING FROM INTERNAL WAVE BREAKING