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On the evolution of full-field stratified turbulence

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Decaying turbulence in the presence of a background density stratification is studied by means of direct numerical simulations. The turbulent integral lengthscales are monitored as they evolve in time, and the predictions from recent scaling arguments are tested. Taylor’s assumption in the form epsilon=uh^3/lh (where epsilon is the kinetic energy dissipation rate, uh the horizontal RMS velocity and lh the horizontal integral lengthscale) is often used in the context of forced stratified turbulence simulations, albeit without confirmation of its validity. Our decaying simulations allow us to test the validity of Taylor’s assumption in stratified turbulent flows. Finally, we look at the decay of the horizontal kinetic energy, and find that the decay rate is in line with recent theoretical results.

Author(s):

Andrea Maffioli    
University of Cambridge
United Kingdom

Peter Davidson    
University of Cambridge
United Kingdom

P.K. Yeung    
Georgia Institute of Technology
United States