Dissipation in unsteady turbulence

Recent experiments and simulations have shown that unsteady turbulent flows display a universal behavior at short and intermediate times, different from classical scaling relations. The origin of these observations is explained using a nonequilibrium correction to Kolmogorov's energy spectrum, and the exact form of the observed universal scaling is derived.

Figure 1

The prediction of the normalized dissipation rate as a function of the Reynolds number ratio $R_{\lambda }/{\overline{R}}_{\lambda }$, expressions (25) and (29), compared to numerical [19] and experimental [10] results.

Figure 2

The prediction of the ratio of the Taylor scale to the integral scale on the Reynolds number ratio $R_{\lambda }/{\overline{R}}_{\lambda }$, compared to experimental [10] results.