MATHEMATICAL SCIENCES

Progress has been made in the study of multi-scale dynamics in flow-oriented rotary channels


Flows in a rotating frame of reference are widely found in geophysics, astrophysics, and engineering. For example, ocean flows, atmospheric flows, and flows in turbomachinery. Wall turbulence is an important fundamental problem in the study of fluid mechanics. In wall turbulence, system rotation has an important impact on the multiscale dynamics and coherent structure of 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 predict, optimize or control the flow in nature and engineering. 

Recently, the Aerospace Vehicle Flow Numerical Simulation Research Group of the Institute of Mechanics of the Chinese Academy of Sciences has carried out research on multi-scale dynamics in the flow direction rotation channel. In this work, the generalized Kolmogorov equation is used to explore the influence of rotation on the energy balance of wall turbulence, and the multi-scale characteristics of inclined vortices are discovered for the first time. Furthermore, 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 (among them, 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 turbulent flows, which has guiding significance for the influence of rotation on turbulent flow regimes in general wall flows. 

The research results were published in the Journal of Fluid Mechanics under the title of Multiscale dynamics in streamwise-rotating channel turbulence. The research work was supported by the National Key R&D Program of China and the National Natural Science Foundation of China. (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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