Vesicle tumbling inhibited by inertia

Laadhari, Aymen; Saramito, Pierre; Misbah, Chaouqi

doi:10.1063/1.3690862

Cited by 41 publications

(61 citation statements)

References 17 publications

(7 reference statements)

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“…In that previous work, it was shown that a vesicle that should be tumbling in a viscous flow will tank-tread when the Reynolds number is increased. More recently Laadhari, Saramito & Misbah (2012) have observed similar behaviour.…”

Section: Introductionsupporting

confidence: 60%

Reynolds number effects on lipid vesicles

Salac

Miksis

2012

J. Fluid Mech.

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Vesicles exposed to the human circulatory system experience a wide range of flows and Reynolds numbers. Previous investigations of vesicles in fluid flow have focused on the Stokes flow regime. In this work the influence of inertia on the dynamics of a vesicle in a shearing flow is investigated using a novel level-set computational method in two dimensions. A detailed analysis of the behaviour of a single vesicle at finite Reynolds number is presented. At low Reynolds numbers the results recover vesicle behaviour previously observed for Stokes flow. At moderate Reynolds numbers the classical tumbling behaviour of highly viscous vesicles is no longer observed. Instead, the vesicle is observed to tank-tread, with an equilibrium angle dependent on the Reynolds number and the reduced area of the vesicle. It is shown that a vesicle with an inner/outer fluid viscosity ratio as high as 200 will not tumble if the Reynolds number is as low as 10. A new damped tank-treading behaviour, where the vesicle will briefly oscillate about the equilibrium inclination angle, is also observed. This behaviour is explained by an investigation on the torque acting on a vesicle in shear flow. Scaling laws for vesicles in inertial flows have also been determined. It is observed that quantities such as vesicle tumbling period follow square-root scaling with respect to the Reynolds number. Finally, the maximum tension as a function of the Reynolds number is also determined. It is observed that, as the Reynolds number increases, the maximum tension on the vesicle membrane also increases. This could play a role in the creation of stable pores in vesicle membranes or for the premature destruction of vesicles exposed to the human circulatory system.

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Section: Introductionsupporting

confidence: 60%

Reynolds number effects on lipid vesicles

Salac

Miksis

2012

J. Fluid Mech.

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“…For any explored volume fraction φ, η loc is always found to increase with Re. This effect is attributed to the increase of capsule inclination angle due to inertia (in agreement with the work of Laadhari, Saramito & Misbah (2012)): the particles assume a larger cross-section in the channel, which in turn leads to a larger flow resistance, resulting in a higher local viscosity. This led to two conclusions.…”

Section: Overviewsupporting

confidence: 65%

Soft suspensions: inertia cooperates with flexibility

Misbah

2014

J. Fluid Mech.

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Cross-streamline migration of soft particles in suspensions is essential for cell and DNA sorting, blood flow, polymer processing and so on. Pioneering work by Poiseuille on blood flow in vivo revealed an erythrocyte-free layer close to blood vessel walls. The formation of this layer is related to a viscous lift force caused by cell deformation that pushes cells towards the centre of blood capillaries. This lift force has in this case a strong impact on blood flow. In contrast, rigid spherical particles migrate from the centre towards the periphery, owing to inertia (the Segré-Silberberg effect). An important open issue is to elucidate the interplay between particle deformation and inertia. By using a capsule suspension model, Krueger, Kaoui & Harting (J. Fluid Mech., 2014, vol. 751, pp. 725-745) discovered that capsule flexibility can suppress the Segré-Silberberg effect and inertia promotes overall flow efficiency thanks to a strong inertial flow focusing effect.

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“…(1). At the scale of the RBC the Reynolds number is often small enough (exceptions may occur in the arterioles and at sites of aneurysms, for example, (Laadhari et al, 2012)) so that inertia can be neglected. The vesicle membrane acts on the fluid via bending forces, while the local membrane area remains unstretched; the membrane develops tension forces ζ that prevent extension (or compression).…”

Section: Model and Methodsmentioning

confidence: 99%