Multiscalar Mixing in Turbulent Overturns

Oregon State University, Corvallis OR

Investigators

Abstract

0095640 Smyth Direct numerical simulations of turbulent overturns will be extended to case more directly relevant to the ocean thermocline. The present results based on simulations of turbulence developing and decaying in an unforced shear layer show that mixing is more efficient in the pre-turbulent developing phase than in the fully turbulent decaying phase. The speculation is that the observed difference in mixing efficiency among the various ocean flow regimes depends on the relative time spent in the pre-turbulent phase as opposed to the fully developed turbulence. If so, then the nature of the forcing may determine the efficiency of mixing, a valuable simplification. A series of experiments with steady and episodic forcing will conducted to test this conjecture. In addition, numerical simulations will examine differential diffusion in unforced and forced overturns to determine under which circumstances it is most important.