Unsteady dissipation scaling in static and active grid turbulence
Y. Zheng, K. Nakamura, K. Nagata, and T. Watanabe Unsteady dissipation scaling in static- and active-grid turbulence Journal of Fluid Mechanics, 956 A20 2022 This article may be found at https://doi.org/10.1017/jfm.2022.937 . Accepted manuscript is available here. This version is free to view and download for private research and study only. Abstract A new time-dependent analysis of the global and local fluctuating velocity signals in grid turbulence is conducted to assess the scaling laws for non-equilibrium turbulence. Experimental datasets of static- and active-grid turbulence with different Rossby numbers Ro(=U/ΩM: U is the mean velocity, Ω is the mean rotation rate and M is the grid mesh size) are considered. Although the global (long-time-averaged) non-dimensional dissipation rate Cε is independent of the Reynolds number Reλ based on the global Taylor microscale, the local (short-time-averaged) non-dimensional dissipation rate ⟨Cε(ti)⟩ (ti is the local time) both in the static