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Homogeneous isotropic turbulence in dilute polymers. (English) Zbl 1070.76030

Summary: The modification of the turbulent cascade by polymeric additives is addressed by direct numerical simulations of homogeneous isotropic turbulence of a FENE-P fluid. According to the appropriate form of Kármán-Howarth equation, two kinds of energy fluxes exist, namely the classical transfer term and the coupling with the polymers. Depending on the Deborah number, the response of the flow may result either in a pure damping or in the depletion of small scales accompanied by increased fluctuations at large scale. The latter behaviour corresponds to an overall reduction of the dissipation rate with respect to an equivalent Newtonian flow with identical fluctuation intensity. We discuss the relevance of the position of the crossover scale between two components of energy flux with respect to Taylor microscale of the system.

MSC:

76F05 Isotropic turbulence; homogeneous turbulence
76A10 Viscoelastic fluids
80A20 Heat and mass transfer, heat flow (MSC2010)
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