KOLMOGOROV SCALES IN A DRIVEN CAVITY FLOW

Turbulent flow in a three-dimensional driven cavity has been simulated directly by solving the Navier-Stokes equations. The results at Re = 3200 and 10 000 compare well with the experimental data. Viscous dissi pation rate has been calculated without making the assumption of isotr opy. Near the top moving wall, the instantaneous dissipation rate is v ery high and also has high amplitude. Its frequency increases bur ampl itude decreases as one moves away from the wall and it becomes intermi ttent in the vortex core. The high Reynolds number assumption that dis sipation is mainly due to the fluctuating velocity components is seen to be true in the present case except near the wall. The Kolmogorov le ngth scale attains higher values in the core of the primary vortex due to low dissipation rate there. A value of 0.01 times the size of the cubic cavity is a good representative value at Re = 10 000. Even thoug h the present (84x84x84) grid cannot resolve this scale very well, it can resolve all the scales dynamically significant in the How as seen from the velocity and dissipation spectra. (C) 1998 The Japan Society of Fluid Mechanics Incorporated and Elsevier Science B.V. All rights r eserved.