Some dynamical features of the turbulent flow of a viscoelastic fluid for reduced drag

Abstract

It is well known that the addition of minute amounts of long polymer chains to organic solvents, or water, can lead to significant turbulent drag reduction. In the present study, direct numerical simulations of turbulent channel flow of a viscoelastic fluid, at zeroshear friction Reynolds numbers up to of 1000, are analyzed. Both the mean and turbulent fields are studied, but with a primary focus on the turbulent stress and viscoelastic extrastress (conformation tensor) fields in order to contrast the dynamics of each. An analysis of both the turbulent kinetic energy and the elastic energy budget is made, with emphasis on the interactive dynamics between the two fields.

A methodology to evaluate statistical errors in DNS data of plane channel flows

“…Then E R monotonically decreases (except at Re τ = 4079 ) towards the center of the channel, with negative values beyond y + ≈ 170 . Moser et al [20] and Thais et al [24] present increasing E R (y + ) values until y + ≈ 175 and decreasing values towards the center of the channel. Hoyas and Jiménez [10] present small oscillating E R (y + ) values over the entire domain.…”

“…Thais et al [24] present results of DNS of Newtonian and viscoelastic flows for different Reynolds numbers, from Re τ = 180 up to 30 0 0. In the present work we only consider the Newtonian flow at Re τ = 590 and 10 0 0.…”

“…[2] -Hoyas and Jiménez [10] -Lozano-Durán and Jiménez [14] ; (ii) Bernardini et al [4] ; (iii) Moser et al [20] -Lee and Moser [13] ; (iv) Thais et al [24] ; and (v) Vreman and Kuerten [27] , 28 ].…”

“…the residual E R (y + ) , i.e., the difference between R + yx and ˆ R + yx . AJZM [2] ; BPO [4] ; HJ [10] ; LDJ [14] ; LM [13] ; MKM [15] ; TGM [24] ; VK [28] . …”

Small scale dynamics of isotropic viscoelastic turbulence

“…However, our value for the diffusivity is significantly smaller than in other schemes. For comparison, in their DNS of channel flow, Sureshkumar et al [46] used ν f ν a ≈ 0.8 and at the high resolution, Thais et al [50] used…”