Title: Comparison of heat-transfer reduction in drag-reduced turbulent channel flows with different fluid and thermal boundary conditions

Authors: T. Tsukahara, Y. Kawaguchi

Addresses: Department of Mechanical Engineering, Tokyo University of Science, Yamazaki 2641, Noda-shi, Chiba, 278-8510, Japan. ' Department of Mechanical Engineering, Tokyo University of Science, Yamazaki 2641, Noda-shi, Chiba, 278-8510, Japan

Abstract: Direct numerical simulations of drag-reduced viscoelastic turbulent channel flow with heat transfer were carried out for four kinds of rheologically different fluids, that is, with different values of Weissenberg number and viscosity ratio. Two different thermal boundary conditions were considered. We present the budget of temperature variance and the relationship between the Heat-Transfer Reduction (HTR) and the Drag Reduction (DR) for each rheologically-different fluid. A case with a low viscosity ratio was found to give rise to high DR, with relatively low HTR compared with that obtained with a high Weissenberg number, suggesting dissimilarity between the heat and momentum transports.

Keywords: turbulent channel flow; DNS; direct numerical simulation; drag reduction; Giesekus model; non-Newtonian fluids; rheology; momentum transport; Toms effect; turbulence control; turbulent heat transfer; viscoelastic fuids; Weissenberg number; viscosity ratio; thermal boundary conditions; temperature variance.

DOI: 10.1504/PCFD.2011.041022

Progress in Computational Fluid Dynamics, An International Journal, 2011 Vol.11 No.3/4, pp.215 - 225

Published online: 28 Jun 2011 *

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