PhD - Offre de thèse à Nice: Dynamics of impinging jets

The recent democratization of 3D printers has created a new excitement in the scientific community around the impact of liquid microjets on substrates. Jets are also key tools for cleaning and cooling surfaces in microelectronics. The impact of a submillimeter liquid jet (typically 10-100 microns in diameter) raises questions about the experimental realization and morphogenesis of the deposited liquid film: beyond a certain impact speed of the jet, the deposit destabilizes and gives rise to a particular morphology, known as hydraulic jump, characterized by very strong variations in height and a high sensitivity to external conditions. For the optimization of 3D printing, increasing the printing speed by a higher jet velocity should bring a breakthrough in printing technologies if undesirable hydrodynamic instabilities are avoided.

This project aims to shed light on the dynamics of jets hitting a surface. This is a complex problem that requires very ambitious experimental, numerical and modeling work, as it involves many physical effects and subtle couplings between them. The dynamics of the impact of a jet will be strongly influenced by the presence of a free deformable interface, the effects of heat transfer and phase change in contact with a heated or cooled substrate, the occurrence of turbulent flows, or the addition of fibers in the liquid as it may be the case to enhance the mechanical properties of printed objects.

Our approach, both experimental, numerical and theoretical, has already been supported and validated by the ANR in the framework of the IJET project led by Médéric Argentina, who will be the thesis supervisor.

This thesis subject is part of the development of an activity in our research group, related to the dynamics of impacting jets. This research is fully within the scope of the ANR IJET, which the thesis director is responsible for.