The contribution of dilatational motion to energy flux in homogeneous compressible turbulence

Fuente: arXiv
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Autori principali: Luo, Chensheng, Fang, Le, Fang, Jian, Xu, Haitao, Pumir, Alain, Yang, Ping-Fan
Natura: Preprint
Pubblicazione: 2025
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author Luo, Chensheng
Fang, Le
Fang, Jian
Xu, Haitao
Pumir, Alain
Yang, Ping-Fan
author_facet Luo, Chensheng
Fang, Le
Fang, Jian
Xu, Haitao
Pumir, Alain
Yang, Ping-Fan
contents We analyze the energy flux in compressible turbulence by generalizing the exact decomposition recently proposed by Johnson (Phys. Rev. Lett., vol. 124, 2020. 104501) to study incompressible turbulent flows. This allows us to characterize the effect of dilatational motion on the inter-scale energy transfer in three-dimensional compressible turbulence. Our analysis reveals that the contribution of dilatational motion to energy transfer is due to three different physical mechanisms: the interaction between dilatation and strain, between dilatation and vorticity, and the self-interaction of dilatational motion across scales. By analyzing numerical simulations of flows at moderate turbulent Mach numbers ($Ma_t \lesssim 0.3$), we validate our theoretical derivations and provide a quantitative description of the role of dilatational motion in energy transfer. In particular, we determine the scaling dependence of the dilatational contributions on the turbulent Mach number. Moreover, our findings reveal that the eddy-viscosity assumption often used in large-eddy simulations, in the spirit of the approach used for incompressible flows, effectively neglects the interaction between solenoidal-dilatational energy transfer and overestimate dilatational effects.
format Preprint
id arxiv_https___arxiv_org_abs_2502_07349
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The contribution of dilatational motion to energy flux in homogeneous compressible turbulence
Luo, Chensheng
Fang, Le
Fang, Jian
Xu, Haitao
Pumir, Alain
Yang, Ping-Fan
Fluid Dynamics
We analyze the energy flux in compressible turbulence by generalizing the exact decomposition recently proposed by Johnson (Phys. Rev. Lett., vol. 124, 2020. 104501) to study incompressible turbulent flows. This allows us to characterize the effect of dilatational motion on the inter-scale energy transfer in three-dimensional compressible turbulence. Our analysis reveals that the contribution of dilatational motion to energy transfer is due to three different physical mechanisms: the interaction between dilatation and strain, between dilatation and vorticity, and the self-interaction of dilatational motion across scales. By analyzing numerical simulations of flows at moderate turbulent Mach numbers ($Ma_t \lesssim 0.3$), we validate our theoretical derivations and provide a quantitative description of the role of dilatational motion in energy transfer. In particular, we determine the scaling dependence of the dilatational contributions on the turbulent Mach number. Moreover, our findings reveal that the eddy-viscosity assumption often used in large-eddy simulations, in the spirit of the approach used for incompressible flows, effectively neglects the interaction between solenoidal-dilatational energy transfer and overestimate dilatational effects.
title The contribution of dilatational motion to energy flux in homogeneous compressible turbulence
topic Fluid Dynamics
url https://arxiv.org/abs/2502.07349