Direct simulation of stably stratified homogeneous turbulent shear flows
Abstract
A simple and efficient numerical method for investigating homogeneous turbulent shear flows with stable stratification is described. Simulation results are reported which show that a countergradient heat flux (CGHF) occurs in a stably stratified, initially turbulent shear flow if the thermal dissipation rate is too small to limit the ratio of potential energy relative to kinetic energy. Large potential energy may originate either from the initial conditions or is produced by velocity fluctuations in stratified flow if the Richardson number is significantly larger than a critical value of about 0.2. High Prandtl number flows are more likely to exhibit the CGHF phenomenon than low Prandtl number cases. The largescale vortex structures developing in homogeneous shear flows break into smallscale features when the flow is supercritically stratified and their inclination angle is lowered.
 Publication:

8th Symposium on Turbulence and Diffusion
 Pub Date:
 1988
 Bibcode:
 1988sytd.proc...66G
 Keywords:

 Computational Fluid Dynamics;
 Flow Stability;
 Homogeneous Turbulence;
 Shear Flow;
 Stratified Flow;
 Turbulent Flow;
 NavierStokes Equation;
 Prandtl Number;
 Richardson Number;
 Vorticity;
 Fluid Mechanics and Heat Transfer