Turbulent duct flow with polymers

Shahmardi, Armin; Zade, Sagar; Ardekani, Mehdi Niazi; Poole, Robert J.; Lundell, Fredrik; Rosti, Marco E.; Brandt, Luca

doi:10.1017/jfm.2018.858

Cited by 35 publications

(28 citation statements)

References 63 publications

(115 reference statements)

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“…The spanwise correlation also increases when increasing Bi as the velocity streaks become wider than in a Newtonian fluid, despite the existence of yielded regions in the channel core (see figure 16). Note also that, the increased correlation lengths in both the streamwise and spanwise directions, are not limited to the near wall-regions occupied by the streaky structures, as in the other drag reducing flows cited above (García-Mayoral & Jiménez 2011;Dubief et al 2004;Shahmardi et al 2018), but extends up to the centerline. However, this increased spanwise correlation does not extend towards the centreline as much as the streamwise coherence.…”

Section: Turbulent Flowmentioning

confidence: 75%

“…There exists a large literature on the turbulent flow with polymer additives, with the main focus being the drag reduction (Logan 1972;Pinho & Whitelaw 1990;Escudier & Presti 1996;Den Toonder et al 1997;Beris & Dimitropoulos 1999;Warholic et al 1999;Escudier et al 1999;Escudier & Smith 2001;Dubief et al 2004Dubief et al , 2005Escudier et al 2005Escudier et al , 2009Xi & Graham 2010;Owolabi et al 2017;Shahmardi et al 2018). The interested reader is refereed to the work by Berman (1978) and White & Mungal (2008) for a through review on the subject.…”

Section: Friction Losses and Drag Reductionmentioning

confidence: 99%

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Turbulent channel flow of an elastoviscoplastic fluid

et al. 2018

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We present numerical simulations of laminar and turbulent channel flow of an elastoviscoplastic fluid. The non-Newtonian flow is simulated by solving the full incompressible Navier-Stokes equations coupled with the evolution equation for the elastoviscoplastic stress tensor. The laminar simulations are carried out for a wide range of Reynolds numbers, Bingham numbers and ratios of the fluid and total viscosity, while the turbulent flow simulations are performed at a fixed bulk Reynolds number equal to 2800 and weak elasticity. We show that in the laminar flow regime the friction factor increases monotonically with the Bingham number (yield stress) and decreases with the viscosity ratio, while in the turbulent regime the the friction factor is almost independent of the viscosity ratio and decreases with the Bingham number, until the flow eventually returns to a fully laminar condition for large enough yield stresses. Three main regimes are found in the turbulent case, depending on the Bingham number: for low values, the friction Reynolds number and the turbulent flow statistics only slightly differ from those of a Newtonian fluid; for intermediate values of the Bingham number, the fluctuations increase and the inertial equilibrium range is lost. Finally, for higher values the flow completely laminarises. These different behaviors are associated with a progressive increases of the volume where the fluid is not yielded, growing from the centerline towards the walls as the Bingham number increases. The unyielded region interacts with the near-wall structures, forming preferentially above the high speed streaks. In particular, the near-wall streaks and the associated quasi-streamwise vortices are strongly enhanced in an highly elastoviscoplastic fluid and the flow becomes more correlated in the streamwise direction.

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Section: Turbulent Flowmentioning

confidence: 75%

Section: Friction Losses and Drag Reductionmentioning

confidence: 99%

Turbulent channel flow of an elastoviscoplastic fluid

et al. 2018

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“…The time integration is based on an explicit fractional-step method [51], where only the solid hyperelastic contribution in equation (1) is advanced with the Crank-Nicolson scheme, while, all the other terms are advanced with the third order Runge-Kutta scheme [52]. All the spatial derivatives are approximated with the second-order centred finite differences scheme, except for the advection term in equations (5) and (9) where the fifthorder weighted essentially non-oscillatory scheme is applied ( [50,53,54]). A comprehensive review on the effect of different discretization schemes for the advection terms was studied by [52].…”

Section: B Numerical Methodsmentioning

confidence: 99%

Inertial migration of a deformable particle in pipe flow

2019

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We perform fully Eulerian numerical simulations of an initially spherical hyperelastic particle suspended in a Newtonian pressure-driven flow in a cylindrical straight pipe. We study the full particle migration and deformation for different Reynolds numbers and for various levels of particle elasticity, to disentangle the interplay of inertia and elasticity on the particle focusing. We observe that the particle deforms and undergoes a lateral displacement while traveling downstream through the pipe, finally focusing at the pipe centerline. We note that the migration dynamics and the final equilibrium position are almost independent of the Reynolds number, while they strongly depend on the particle elasticity; in particular, the migration is faster as the elasticity increases (i.e. the particle is more deformable), with the particle reaching the final equilibrium position at the centerline in shorter times. Our simulations show that the results are not affected by the particle initial conditions, position and velocity. Finally, we explain the particle migration by computing the total force acting on the particle and its different components, viscous and elastic.

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“…This may seem reasonable at first, but it is not consistent with the measured results of turbulence fluctuation intensity, because the effect of drag reducers is not only to reduce the intensity of turbulence, but also to change the vortex structure of turbulence. Downstream of the area where the drag reducer is added, the hairpin vortex along the shear layer is significantly reduced, and the energy loss caused by the corresponding vortex is reduced [16,17].…”

Section: Turbulence Suppression Hypothesismentioning

confidence: 99%

Research Progress on the Collaborative Drag Reduction Effect of Polymers and Surfactants

Mou

et al. 2020

Materials

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Polymer additives and surfactants as drag reduction agents have been widely used in the field of fluid drag reduction. Polymer additives can reduce drag effectively with only a small amount, but they degrade easily. Surfactants have an anti-degradation ability. This paper categorizes the mechanism of drag reducing agents and the influencing factors of drag reduction characteristics. The factors affecting the degradation of polymer additives and the anti-degradation properties of surfactants are discussed. A mixture of polymer additive and surfactant has the characteristics of high shear resistance, a lower critical micelle concentration (CMC), and a good drag reduction effect at higher Reynolds numbers. Therefore, this paper focuses more on a drag reducing agent mixed with a polymer and a surfactant, including the mechanism model, drag reduction characteristics, and anti-degradation ability.

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Turbulent duct flow with polymers

Cited by 35 publications

References 63 publications

Turbulent channel flow of an elastoviscoplastic fluid

Turbulent channel flow of an elastoviscoplastic fluid

Inertial migration of a deformable particle in pipe flow

Research Progress on the Collaborative Drag Reduction Effect of Polymers and Surfactants

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