Publications de Lailai Zhu | EPFL Graph Search

The Hydrodynamics of a Micro-Rocket Propelled by a Deformable Bubble

François Gallaire, Giacomo Gallino, Lailai Zhu

We perform simulations to study the hydrodynamics of a conical-shaped swimming micro-robot that ejects catalytically produced bubbles from its inside. We underline the nontrivial dependency of the swimming velocity on the bubble deformability and on the ge ...

2019

Film thickness distribution in gravity-driven pancake-shaped droplets rising in a Hele-Shaw cell

Gioele Mariano Nicolò Balestra, François Gallaire, Isha Shukla, Lailai Zhu, Nicolas Igor Jacques Kofman

We study here experimentally, numerically and using a lubrication approach, the shape, velocity and lubrication film thickness distribution of a droplet rising in a vertical Hele-Shaw cell. The droplet is surrounded by a stationary immiscible fluid and mov ...

Cambridge University Press2019

Inertial manipulation of bubbles in rectangular microfluidic channels

Demetri Psaltis, Gioele Mariano Nicolò Balestra, François Gallaire, Seyyed Mohammad Hosseini Hashemi, Miguel Antonio Modestino, Lailai Zhu, Pooria Hadikhani

Inertial microfluidics is an active field of research that deals with crossflow positioning of the suspended entities in microflows. Until now, the majority of the studies have focused on the behavior of rigid particles in order to provide guidelines for m ...

2018

Viscous Taylor droplets in axisymmetric and planar tubes: from Bretherton’s theory to empirical models

Gioele Mariano Nicolò Balestra, François Gallaire, Lailai Zhu

The aim of this study is to derive accurate models for quantities characterizing the dynamics of droplets of non-vanishing viscosity in capillaries. In particular, we propose models for the uniform-film thickness separating the droplet from the tube walls, ...

2018

Bifurcation Dynamics of a Particle-Encapsulating Droplet in Shear Flow

François Gallaire, Lailai Zhu

To understand the behavior of composite fluid particles such as nucleated cells and double emulsions in flow, we study a finite-size particle encapsulated in a deforming droplet under shear flow as a model system. In addition to its concentric particle-dro ...

American Physical Society2017

Swimming with a cage: low-Reynolds-number locomotion inside a droplet

François Gallaire, Lailai Zhu

Inspired by recent experiments using synthetic microswimmers to manipulate droplets, we investigate the low-Reynolds-number locomotion of a model swimmer (a spherical squirmer) encapsulated inside a droplet of a comparable size in another viscous fluid. Me ...

Royal Society of Chemistry2017

The stability of a rising droplet: an inertialess non-modal growth mechanism

François Gallaire, Giacomo Gallino, Lailai Zhu

Prior modal stability analysis (Kojima et al., Phys. Fluids, vol. 27, 1984, pp. 19-32) predicted that a rising or sedimenting droplet in a viscous fluid is stable in the presence of surface tension no matter how small, in contrast to experimental and numer ...

Cambridge University Press2016

A pancake droplet translating in a Hele-Shaw cell: lubrication film and flow field

François Gallaire, Lailai Zhu

We adopt a boundary integral method to study the dynamics of a translating droplet confined in a Hele-Shaw cell in the Stokes regime. The droplet is driven by the motion of the ambient fluid with the same viscosity. We characterize the three-dimensional (3 ...

Cambridge University Press2016

The dynamics of a capsule in a wall-bounded oscillating shear flow

Lailai Zhu

The motion of an initially spherical capsule in a wall-bounded oscillating shear flow is investigated via an accelerated boundary integral implementation. The neo-Hookean model is used as the constitutive law of the capsule membrane. The maximum wall-norma ...

Amer Inst Physics2015

The motion of a deforming capsule through a corner

Lailai Zhu

A three-dimensional deformable capsule convected through a square duct with a corner is studied via numerical simulations. We develop an accelerated boundary integral implementation adapted to general geometries and boundary conditions. A global spectral m ...

Cambridge University Press2015

Squirming through shear-thinning fluids

Lailai Zhu

Many micro-organisms find themselves immersed in fluids displaying non-Newtonian rheological properties such as viscoelasticity and shear-thinning viscosity. The effects of viscoelasticity on swimming at low Reynolds numbers have already received considera ...

Cambridge University Press2015

Motion of an elastic capsule in a constricted microchannel

Lailai Zhu, Cecilia Rorai

We study the motion of an elastic capsule through a microchannel characterized by a localized constriction. We consider a capsule with a stress-free spherical shape and impose its steady-state configuration in an infinitely long straight channel as the ini ...

2015

A microfluidic device to sort capsules by deformability: A numerical study

Lailai Zhu, Cecilia Rorai

Guided by extensive numerical simulations, we propose a microfluidic device that can sort elastic capsules by their deformability. The device consists of a duct embedded with a semi-cylindrical obstacle, and a diffuser which further enhances the sorting ca ...

Royal Society of Chemistry2014