Journal ArticleDOI
Polymer-induced drag reduction: Effects of the variations in elasticity and inertia in turbulent viscoelastic channel flow
TLDR
In this article, the effects of the flow elasticity and inertia in polymer-induced drag reduction through (pseudo)spectral simulations of a turbulent channel flow of a dilute polymer solution are investigated.Abstract:
In this work we systematically investigate the effects of the flow elasticity and inertia in polymer-induced drag reduction through (pseudo)spectral simulations of a turbulent channel flow of a dilute polymer solution. Viscoelastic effects are modeled by the finite-extensibility nonlinear elastic dumbbell model with the Peterlin approximation. The present work updates the low Weissenberg results (Weτ0⩽50) reported in earlier works by Sureshkumar et al. [Phys. Fluids 9, 743 (1997)] and Dimitropoulos et al. [J. Non-Newtonian Fluid Mech. 79, 433 (1998)] for a zero shear rate friction Reynolds number, Reτ0=125, by allowing for a lower value for the numerical diffusivity. In addition, we examine two effects on drag reduction: (A) high elasticity, by varying Weτ0 from 62.5 to 125 for a constant Reτ0=125, (B) friction Reynolds number, Reτ0=180, 395, and 590, for a constant Weτ0=50. In the high elasticity region, the mean Reynolds, Remean, continues to increase with increasing Weτ0, albeit at a smaller rate. Thus...read more
Citations
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Journal ArticleDOI
Turbulent drag reduction in dam-break flows
TL;DR: In this paper, the role of turbulence in dam-break flows is investigated, where a finite volume of fluid is released from a compartment into a long, rectangular channel and a gravity current, undular bore, or solitary wave develops, depending on the ambient fluid height in the channel.
Journal ArticleDOI
Drag reduction and the dynamics of turbulence in simple and complex fluidsa)
TL;DR: In this paper, the authors describe simulations of turbulent minimal channel flow of Newtonian fluids and viscoelastic polymer solutions and show that there are intervals of hibernating turbulence that display very low drag as well as many other features of the maximum drag reduction observed in polymer solutions.
Journal ArticleDOI
Influence of rheological parameters on polymer induced turbulent drag reduction
TL;DR: In this paper, the authors performed direct numerical simulations of polymer induced drag reduction in turbulent channel flows up to the maximum drag reduction (MDR) limit using a fully spectral method in conjunction with kinetic theory based elastic dumbbell models for the description of polymer chain dynamics.
Journal ArticleDOI
Numerical Methods for Viscoelastic Fluid Flows
TL;DR: In this paper, the addition of macromolecules to a solvent imparts viscoelasticity to the solvability of complex fluids, which can be used for specific applications.
Journal ArticleDOI
Polymer drag reduction in exact coherent structures of plane shear flow
TL;DR: In this article, the authors studied the effect of viscoelasticity on the velocity field for the exact coherent states, i.e., counter-rotating pairs of streamwise-aligned vortices flanking a low-speed streak in the streamwise velocity.
References
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Journal ArticleDOI
Turbulence statistics in fully developed channel flow at low reynolds number
TL;DR: In this article, a direct numerical simulation of a turbulent channel flow is performed, where the unsteady Navier-Stokes equations are solved numerically at a Reynolds number of 3300, based on the mean centerline velocity and channel half-width, with about 4 million grid points.
Journal ArticleDOI
Direct numerical simulation of turbulent channel flow up to Reτ=590
TL;DR: In this paper, numerical simulations of fully developed turbulent channel flow at three Reynolds numbers up to Reτ=590 were reported, and it was noted that the higher Reynolds number simulations exhibit fewer low Reynolds number effects than previous simulations at Reτ = 180.
Journal ArticleDOI
Drag reduction fundamentals
TL;DR: In this paper, the effects of dilute solutions of linear, random-coiling macromolecules in turbulent pipe flow is reviewed. And the experimental evidence is emphasized in three sections concerned with the graphical display of established features of the phenomenon, data correlation and analysis, and the physical mechanism of drag reduction.
Book
Fluid dynamics of viscoelastic liquids
TL;DR: In this article, a mathematical and physical theory which takes a proper account of the elasticity of liquids is developed, which leads to systems of partial differential equations of composite type in which some variables are hyperbolic and others elliptic.