Direct numerical simulations of homogeneous turbulence in density-stratified fluids

TLDR

Simulations across a range of initial Froude numbers and two theoretical approaches were used to study stratification effects during turbulence decay. Direct numerical simulations show that while stratification induces wave‑like features, strong nonlinear spectral energy transfer persists, with selective suppression of certain transfer modes.

Abstract

We report on the results of direct numerical simulations of the decay of homogeneous turbulence in density‐stratified fluids. The effects of stratification are examined by performing simulations for a range of different initial Froude numbers. Also two theoretical approaches are presented, which are applicable in the later stages of decay. For the conditions computed, although the stritification introduced definite wave‐like characteristics into the flow‐fields, the non‐linearity, as expressed for example by the spectral energy transfer, remained strong. However, the selective suppression of certain types of transfer was observed to occur.