TURBULENCE IN A STRATIFIED FLUID - WHEN IS THE ENERGY SPECTRUM NON-KOLMOGOROV?

Homogeneous isotropic turbulence in a fluid is characterized by an energy spectrum which follows the so-called Kolmogorov's 5/3 law. It had been expected that for a stratified fluid a different scaling - namely a 11/5 law due to Bolgiano and Obukhov would be seen. However, there has been a lot of controversy regarding when and where deviations from the Kolmogorov spectrum would be observed. In this talk, we will start from scratch ( assuming nothing except the existence of Navier-Stokes equation ) and explain under what circumstances, the 11/5 scaling should be clearly seen.