Turbulence transition in stratified atmospheric and oceanic shear flows: Reynolds and Prandtl number controls upon the mechanism

Abstract

We provide detailed analyses of the role of secondary instabilities in the transition to turbulence of stratified shear flows at the high Reynolds and Prandtl numbers appropriate to the atmosphere and ocean. Our focus is upon a series of recent observations suggestive of a marked change in the mechanism of transition in this laboratory inaccessible regime. Our results demonstrate the joint dependance of the transition mechanism on these two nondimensional parameters. We discuss the primary transition mechanisms of shear aligned convective instability, stagnation point instability and shear instabilities of the braid in detail. Copyright 2011 by the American Geophysical Union.