Insights into turbulent free-shear-layer dynamics from vortex-gas computations and statistical mechanics

Abstract

The word „turbulence‟ is most commonly encountered during an in-flight announcement urging passengers to fasten seat-belts, in anticipation of unsteadiness due to the large scale turbulent motion in the atmosphere. However, turbulent flows are ubiquitous over a wide range of technologically relevant scenarios including energy, transportation and weather prediction. When the inertia associated with a fluid flow becomes much larger than the frictional forces due to viscosity (the ratio UL/ is the Reynolds number), the smooth laminar flow transitions to turbulence (Reynolds, 1895) characterized by unsteady, multi-scaled, chaotic (Gollub & Swinney 1975, Maurer & Libchaber 1979) and rotational flow. This transition can often be observed in a faucet.