Flows in rotating reference frames are widely found in geophysics, astrophysics, and engineering, such as ocean flows, atmospheric flows, and flows in impeller machinery. Wall turbulence is also an important fundamental problem in fluid mechanics research. In wall turbulence, system rotation can have an important impact on the multiscale dynamics and coherent structure of the turbulence. Therefore, it is of great significance to study the influence of system rotation on the multi-scale dynamics of wall turbulence in rotating systems, and to better understand the nature of wall turbulence in rotating systems and to predict, optimize or control the related flows in nature and engineering.
The Aerospace Vehicle Flow Numerical Simulation Research Group of the Institute of Mechanics of the Chinese Academy of Sciences has recently carried out research on multi-scale dynamics in the flow direction rotating channel. In this work, the effect of rotation on the energy balance of wall turbulence was first investigated using the generalized Kolmogorov equation, during which the multi-scale characteristics of inclined vortices were discovered for the first time. Then, through the Reynolds stress equilibrium equation and the hairpin vortex model, it is inferred that the correlation between Coriolis force and pressure velocity is the main reason for maintaining the inclined vortex, and the Coriolis force term has a dual effect. This work has carried out in-depth research on the multi-scale characteristics and maintenance mechanisms of rotating wall turbulence, which has guiding significance for the influence of rotation on turbulent flow regimes in general wall flow.
The work was published in the Journal of Fluid Mechanics under the title “Multiscale dynamics in streamwise-rotating channel turbulence”. Hu Running, a doctoral student from the Institute of Mechanics, is the first author of the paper, Associate Researcher Yu Changping is the corresponding author, and the collaborator is Researcher Li Xinliang. This research was supported by the National Key R&D Program of China (2019YFA0405300, 2020YFA0711800) and the National Natural Science Foundation of China (12072349, 12232018, 91852203, 12202457). (Source: Institute of Mechanics, Chinese Academy of Sciences)
Related Paper Information:https://doi.org/10.1017/jfm.2023.691
Wall vortex structure in rotating wall turbulence (top view), stained at wall height
Mechanism analysis of (a) up-throw and (b) downsweep events of hairpin vortex model in the upper half of the channel
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