Drag and lift forces on bubbles in a rotating flow

Nierop, Ernst A. van; Luther, Stefan; Bluemink, J.J.; Magnaudet, Jacques; Prosperetti, Andréa; Lohse, Detlef

doi:10.1017/s0022112006003387

Cited by 66 publications

(69 citation statements)

References 29 publications

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“…and (ii) Which parameters lead to the exiting of particles from the vortex? The answers to these questions are nontrivial due to the complex hydrodynamic interactions of particles in swirling flows (17,(37)(38)(39). Using force models as well 5.…”

Section: Resultsmentioning

confidence: 99%

Unexpected trapping of particles at a T junction

Vigolo

Radl

Stone

2014

Proc. Natl. Acad. Sci. U.S.A.

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A common element in physiological flow networks, as well as most domestic and industrial piping systems, is a T junction that splits the flow into two nearly symmetric streams. It is reasonable to assume that any particles suspended in a fluid that enters the bifurcation will leave it with the fluid. Here we report experimental evidence and a theoretical description of a trapping mechanism for low-density particles in steady and pulsatile flows through Tshaped junctions. This mechanism induces accumulation of particles, which can form stable chains, or give rise to significant growth of bubbles due to coalescence. In particular, low-density material dispersed in the continuous phase fluid interacts with a vortical flow that develops at the T junction. As a result suspended particles can enter the vortices and, for a wide range of common flow conditions, the particles do not leave the bifurcation. Via 3D numerical simulations and a model of the two-phase flow we predict the location of particle accumulation, which is in excellent agreement with experimental data. We identify experimentally, as well as confirm by numerical simulations and a simple force balance, that there is a wide parameter space in which this phenomenon occurs. The trapping effect is expected to be important for the design of particle separation and fractionation devices, as well as used for better understanding of system failures in piping networks relevant to industry and physiology.fluid dynamics | bubble trapping | vortex breakdown | 3D simulations

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Section: Resultsmentioning

confidence: 99%

Unexpected trapping of particles at a T junction

Vigolo

Radl

Stone

2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The bubbles are tracked by solving the following dynamical equation in which their mass is neglected (see, e.g., [13]): in which C A = 1/2 and C L = 1/2 are the added mass and lift coefficients, respectively [14,15]. The drag coefficient is modeled as mentioned in [16,17] as follows:…”

Section: Governing Equations and Numerical Methodsmentioning

confidence: 99%

Effect of vapor bubbles on velocity fluctuations and dissipation rates in bubbly Rayleigh-Bénard convection

et al. 2011

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. (2011). Effect of vapor bubbles on velocity fluctuations and dissipation rates in bubbly Rayleigh-Bénard convection. Physical Review E, 84(3), 036312-1/7. [036312]. DOI: 10.1103/PhysRevE.84.036312 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Numerical results for kinetic and thermal energy dissipation rates in bubbly Rayleigh-Bénard convection are reported. Bubbles have a twofold effect on the flow: on the one hand, they absorb or release heat to the surrounding liquid phase, thus tending to decrease the temperature differences responsible for the convective motion; but on the other hand, the absorbed heat causes the bubbles to grow, thus increasing their buoyancy and enhancing turbulence (or, more properly, pseudoturbulence) by generating velocity fluctuations. This enhancement depends on the ratio of the sensible heat to the latent heat of the phase change, given by the Jakob number, which determines the dynamics of the bubble growth.

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“…The uncertainty with which many of the terms of this equation are known is well appreciated in the literature (see e.g. [19] or our own work [20]). Moreover, due to interaction with the wake, there might be history forces which have been neglected in (11) [21,22,23].…”

Section: Modelmentioning

confidence: 98%

Heat transfer mechanisms in bubbly Rayleigh-Bénard convection

et al. 2009

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The heat transfer mechanism in Rayleigh-Bénard convection in a liquid with a mean temperature close to its boiling point is studied through numerical simulations with point-like vapor bubbles, which are allowed to grow or shrink through evaporation and condensation and which act back on the flow both thermally and mechanically. It is shown that the effect of the bubbles is strongly dependent on the ratio of the sensible heat to the latent heat as embodied in the Jacob number Ja. For very small Ja the bubbles stabilize the flow by absorbing heat in the warmer regions and releasing it in the colder regions. With an increase in Ja, the added buoyancy due to the bubble growth destabilizes the flow with respect to single-phase convection and considerably increases the Nusselt number.

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Drag and lift forces on bubbles in a rotating flow

Cited by 66 publications

References 29 publications

Unexpected trapping of particles at a T junction

Unexpected trapping of particles at a T junction

Effect of vapor bubbles on velocity fluctuations and dissipation rates in bubbly Rayleigh-Bénard convection

Heat transfer mechanisms in bubbly Rayleigh-Bénard convection

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