Statistically steady turbulence in thin films: direct numerical simulations with Ekman friction

Prasad Perlekar, Rahul Pandit
2009 New Journal of Physics  
We present a detailed direct numerical simulation (DNS) of the two-dimensional Navier-Stokes equation with the incompressibility constraint and air-drag-induced Ekman friction; our DNS has been designed to investigate the combined effects of walls and such a friction on turbulence in forced thin films. We concentrate on the forward-cascade regime and show how to extract the isotropic parts of velocity and vorticity structure functions and hence the ratios of multiscaling exponents. We find that
more » ... nents. We find that velocity structure functions display simple scaling, whereas their vorticity counterparts show multiscaling, and the probability distribution function of the Weiss parameter , which distinguishes between regions with centers and saddles, is in quantitative agreement with experiments.
doi:10.1088/1367-2630/11/7/073003 fatcat:x2okssjtrbfwzlebywsqsk35fm