On the correlation between enstrophy and energy dissipation rate in a turbulent wake

Abstract

All three components of the vorticity fluctuation have been measured simultaneously in a turbulent wake using a new eight-sensor vorticity probe. The vorticity fluctuation spectra agree reasonably well with those from a direct numerical simulation of a turbulent channel flow at high wavenumbers. The similarity between the instantaneous energy dissipation rate e and the instantaneous enstrophy ω2 is examined using spectra and probability density functions. The correlation between ω2 and e is evaluated in some detail. The homogeneous value of e is strongly correlated with ω2. The full value of e and, more especially its isotropic value, are less well correlated with the enstrophy. Conditional averaging indicates that high enstrophy regions are associated with high energy dissipation rate regions.