Journal of Fluid Mechanics reports on the research findings on non-equilibrium turbulent energy dissipation

Recently, the research work entitled ‘Energy transfer in turbulent flows behind two side-by-side turbulence fields’ by Dr. Zhou of School of Energy and Power Engineering was published in the top journal of fluid mechanics, Journal of Fluid Mechanics(

This research is a collaboration work between the School of Energy and Power Engineering, Nanjing University of Science and Technology, the School of Aerospace Engineering, Nagoya University, Japan, the School of Mechanical Systems Engineering, Nagoya University, and the Institute of Fluid Science, Tohoku University, Japan. Dr. Zhou is the first author and also the corresponding author of the research, and other main contributors are Prof. Koji Nagata from Nagoya University and Prof. Yasuhiko Sakai from Nagoya University and Prof. Toshiyuki Hayase from Tohoku University.

In 1941, Kolmogorov introduced the K41 hypothesis (local isotropy, Kolmogorov’s first similarity and Kolmogorov’s second similarity) and successfully predicted the existence of an extended -5/3 power-law in the so-called inertial range, and the -5/3power-law proposed by Kolmogorov was a landmark achievement in turbulence theory, which is considered to be able to describe universal feathers of turbulent motions. However, recent studies (both experiments and numerical simulations) have found that when the flow field is highly inhomogeneous, non-isotropic and intermittent (not satisfying the K41 hypothesis), the -5/3 power-law still exists, which imposes a challenge to understand the Kolmogorov -5/3 scaling law. To shed light on this phenomena, this work investigates the characteristics of the two-point energy transfer in a non-uniform non-isotropic flow field through the Karman-Howarth-Monin-Hill equation, and also gives the physical correlation between the single-point energy transfer and the two-point energy transfer. The findings provide new insights into the understanding of the Kolmogorov’s -5/3 power-law. The published work is part a series of investigations on turbulence flows carried out by Dr. Zhou since he joined Nanjing University of Science and Technology (Phys. Rev. Fluids 5, 064604, 2020; J. Fluid Mech., 874, 677, 2019; Phys. Rev. Fluids 4, 124602, 2019; Phys. Rev. Fluids 3, 124604, 2018) after another important research result. The subsequent research on the origin of the -5/3 energy spectra, another important scientific topic, is now ongoing and is expected to lead to further research progress.

This research was supported by the National Natural Science Foundation of China, the Natural Science Foundation of Jiangsu Province, and MEXT KAKENHI, Japan. Also part of this work was performed by using the supercomputer in the Institute of Fluid Science, Tohoku University, Japan.