Grid and subgrid-scale interactions in viscoelastic turbulent flow and implications for modelling

• Published in: Journal of turbulence Vol. 17; no. 6; pp. 543 - 571
• Main Authors: Masoudian, M., da Silva, C.B., Pinho, F.T.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 02.06.2016
• Subjects: Computational fluid dynamics; Constitutive relationships; Direct numerical simulation; Fluid flow; Kinetic energy; large eddy simulation; Mathematical models; polymer drag reduction; small scale intermittency; Turbulence; turbulence modelling: subgrid-scale; Turbulent flow; Viscoelasticity
• ISSN: 1468-5248; 1468-5248
• DOI: 10.1080/14685248.2015.1125492

Using direct numerical simulations of turbulent plane channel flow of homogeneous polymer solutions, described by the Finitely Extensible Nonlinear Elastic-Peterlin (FENE-P) rheological constitutive model, a-priori analyses of the filtered momentum and FENE-P constitutive equations are performed. The influence of the polymer additives on the subgrid-scale (SGS) energy is evaluated by comparing the Newtonian and the viscoelastic flows, and a severe suppression of SGS stresses and energy is observed in the viscoelastic flow. All the terms of the transport equation of the SGS kinetic energy for FENE-P fluids are analysed, and an approximated version of this equation for use in future large eddy simulation closures is suggested. The terms responsible for kinetic energy transfer between grid-scale (GS) and SGS energy (split into forward/backward energy transfer) are evaluated in the presence of polymers. It is observed that the probability and intensity of forward scatter events tend to decrease in the presence of polymers.