New insights into the fine-scale structure of turbulence

In a recent study, Lawson & Dawson (J. Fluid Meck, vol. 780, 2015, pp. 60-98) present experimental results on the fine-scale structure of turbulence, which are obtained with novel variant of particle image velocimetry, to elucidate the relation between the small-scale structure, dynamics and statistics of turbulence. The results are carefully validated against direct numerical simulation data. Their extensive study focuses on the mean structure of the velocity gradient and the pressure Hessian fields for various small-scale flow topologies. It thereby reveals the dynamical impact of turbulent strain and vorticity structures on the velocity gradient statistics through non-local interactions, and points out ways to improve low-dimensional closure models for the dynamics of small-scale turbulence,