The buoyancy range, which represents a transition from large-scale wave-dominated
motions to small-scale turbulence in the oceans and the atmosphere, is investigated
through large-eddy simulations. The model presented here uses a continual forcing
based on large-scale standing internal waves and has a spectral truncation in the
isotropic inertial range. Evidence is presented for a break in the energy spectra from
the anisotropic k−3 buoyancy range to the small-scale
k−5/3 isotropic inertial range.
Density structures that form during wave breaking and periods of high strain rate are
analysed. Elongated vertical structures produced during periods of strong straining
motion are found to collapse in the subsequent vertically compressional phase of the
strain resulting in a zone or patch of mixed fluid.