Computation of Kolmogorov Scales in a Driven Cavity Flow

Kolmogorov microscales have been computed from the data obtained by numerically simulating the turbulent flow at a Reynolds number Re=-l0,000 in a lid driven cavity. It is done by calculating the viscous dissipatjon o and then by finding o, time average of that part which is due to fluctuating velocity components. This part o was found to be much larger than that due to mean velocity components o except near the walls. The Kolmogorov length scale obtained from o and viscosity was found to have larger values in the primary vortex and smaller values outside it where the turbulence activity was more intense. The inviscid estimate of dissipation u/1 is in good qualitative agreement with the exact viscous calculations except near the walls. From the Kolmogorov length scales calculated at all the points in five planes a value of 0.01 times the size of cubic cavity may be taken as a representative value. From the studies made earlier and the present one the (84 x 84 x 84) grid used to simulate the flow at Rc=l0,000 seems to be adequate. TIle Kolmogorov constant C is calculated to be 0.67. This value is somewhat lower because of a low value of Re = 37 based on the Taylor microscale 1,. It is also concluded that the effect of the wall is to decrease C.