Recherche

[FR]
Mon travail de thèse concerne la sédimentation de particules et d’objet flexible. En effet, j’ai étudié la dynamique d’un nuage de particules sédimentant dans un écoulement tourbillonnaire et la déformation d’une fibre flexible chutant dans un fluide visqueux au repos.

[EN]
My PhD work concerns the sedimentation of particles. I studied the dynamic of a cloud of particles settling in a vortical flow and the deformation of a flexible filament settling in a quiescent viscous fluid.

Clouds of particles in vortical flow

The aim of this work is to study experimentally and numerically the influence of a vortical flow on the settling of a cloud of solid spherical particles under gravity at low Stokes number.

We use electro-convection to generate two-dimensional vortical flow and we track the in 3D the trajectory of the cloud. We can measure it velocity, deformation and life-time. We used two numerical two-way coupling simulations to compare experiments. In viscous regime we used Stokeslets and for weak inertia regime, Oseenlet.

Viscous regime: experiments (a) and Stokeslet (b)

Weak inertia regime: experiments (a) and Oseenlet (b)

Deformation of flexible fibers

The aim of this work is to study the deformation, and the dynamic, of flexible fiber settling in a viscous mixture, composed of water and Ucon Oil.
The objective is to catch the stationary deflexion of the fiber, the settling velocity and compare with a new model: the bead-spring model.

An example of the simulation we have done for a flexible fiber, represented by bead-spring model. The beads interact through multibody hydrodynamic interactions and elastic forces.

Bead-spring model