Description of the thesis topic

The project deals with the transport of flexible fibres by a turbulent flow, such as plastic debris or organic matter in oceans and rivers. Modelling the dynamics of such deformable particles in these environmental flows remains a major challenge, particularly near boundaries. Indeed, the presence of a wall makes the flow inhomogeneous and anisotropic, drastically complicating transport properties. So far, the dynamics of fibres in wall-bounded flow have only been considered for rigid particles, while flexible fibres have mainly been studied in the idealized and simpler context of homogeneous isotropic turbulence. Therefore, this PhD project aims to explore the dynamics of flexible fibres in wall-bounded flow, within a turbu-lent channel.

This PhD project aims to explore the dynamics of flexible fibres in wall-bounded flow, within a turbulent channel. The proposed research work will be mainly experimental but will also include a numerical part complementary of the experiments. It will consist in characterizing and understanding the fibre dynamics as a function of the distance from the wall and the flexibility of the particles. Experiments will be con-ducted in the channel flow with fibres of different properties. The fibre orientation and deformation will be measured using several high-speed cameras and 3D reconstruction codes. The experimental results will then be quantitatively compared to results of direct numerical simulations conducted within the team.

Work Context

This PhD thesis is funded through the ANR ChannelFlex project. The student will integrate the Complex Fluids research group of the Physics Institute of Nice (INPHYNI), where a turbulent channel has been recently built and characterized. He or she will also benefit from interactions with other research groups working on numerical and theoretical aspects of turbulent transport, at INPHYNI and in other laboratories of Université Côte d'Azur (INRIA, LJAD).

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival is authorized by the competent authority of the MESR.