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

摘要

Direct numerical simulations of drag-reduced viscoelastic turbulent channel flow with heat transfer were carried out for four kinds of Theologically 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.