Dissipation scales in Navier-Stokes turbulence using highly resolved Direct Numerical Simulations (DNS)

Recent work has shown that turbulent dissipation acquires strong fluctuations and other properties that maintain, even at low enough Reynolds numbers ($Re$), the same relationship with the inertial range, as if $Re$ is very high. In this work we further investigate these conclusions by using highly resolved DNS at a range of $Re$. We highlight the difficulties associated with investigating sub-Kolmogorov scales accurately from numerical as well as statistical standpoints. Results on the time evolution of dissipative modes are presented. The connection of this observation to large-scale and inertial-range dynamics is presented, pointing to potential shortcomings in determining coefficients of the presumed exponential roll off of energy spectrum. Further consequences of these findings are discussed.