Non-linear dynamics is at the heart of sound production in a large variety of musical instrument. Wind instruments (flutes, brasses, woodwinds) relying on self-sustained oscillations are heavily studied at LMA with existing experimental supports. Here, we here aim at developing teaching material to highlight the non-linear behavior of structures when vibrations amplitude become large. Such structures in a musical context correspond percussion instruments such as cymbals or gongs. More precsely, focus is put on the various sounds produced by large gongs, which have proved to display a wide range of behaviours, from linear modal regime to pitch glides or even chaos and wave turbulence.

Semi-anechoic rooms are used by manufacturers for the acoustic characterization of products. The objective of the DADA project is to prove that it is possible to realize a semi-anechoic room with an active technology. The idea is to create a full-scale functional demonstrator whose active system developed would make it possible to erase the acoustic effect of 5 walls (not the floor). This project will make it possible to create the first room with active anechoicity.

Thrombus is a biological material that can be considered as a multilayered, porous and inhomogeneous structure showing permeability gradients. Its role in the unfavorable or favorable evolution of vascular pathology has long been a matter of controversy. Its mechanical characteristics, and the hemodynamic mechanisms involved in its formation and evolution are all parameters that may play a part in the role of the thrombus as a predictive marker of the evolution of pathologies. Its characterization is essential to better understand its role/influence and to propose ad hoc models in in silico simulations.

• Sujet encadré par Gautier VERHILE (IRPHE) & Fabien CANDELIER (IUSTI)

Particle clustering is a key parameter to model aggregation in turbulent flows. For heavy spherical particles, it has been shown that this phenomenon is mainly due to centrifugal forces which expel particles form high vortical regions. For thin flexible particles, the situation seems more complex. Their deformability allow the particle to wrap around the vortex core to follow the streamline. This shape is related to a difference of pressure from each side of the particles, the pressure being higher farther from the vortex core. This pressure difference is responsible of a net force that push the particle toward the vortex core. The balance of this net force and the centrifugal force might be at the origin of a new equilibrium distance from the vortex core (...)

• Sujet encadré par Lounès TADRIST (IUSTI), Irina MARTIN (IUSTI) & Maxime CHINAUD (IUSTI)

Les systèmes et les composants de conversion d'énergie impliquent généralement de la chaleur. Pour assurer le bon fonctionnement de ces systèmes, la chaleur générée doit être contrôlée en créant des architectures fluidiques appropriées. De nombreuses techniques ont été mises en oeuvre pour assurer le transfert de chaleur à l'interface entre une paroi et un fluide (...)

• Sujet encadré par Patrice LE GAL (IRPHE), Benjamin FAVIER (IRPHE), Stephane VIAZZO (M2P2) & Uwe HARLANDER (BTU)

Dans les différents exemples mentionnés précédemment et particulièrement pertinents pour la compréhension de la transition vers la turbulence des écoulements stratifiés géophysiques, l’apparition des instabilités se fait par la résonance d’ondes internes se propageant dans le fluide cisaillé [2,3,4]. Pour l’écoulement de Poiseuille, ce sont les ondes de TollmienSchlichting interagissant avec les ondes de gravité qui donnent naissance à l’instabilité. Pour l’instabilité strato-rotationnelle, il s’agit d’une interaction des ondes gravito-inertielles piégées aux parois alors que l’instabilité barocline s’interprète comme la résonance d’ondes de Rossby se propageant sur des couches séparées verticalement (…)

• Sujet encadré par Christophe ALMARCHA (IRPHE) & Pierre BOIVIN (M2P2)

The scientific consensus on the necessity to reduce the greenhouse gases, like carbon dioxide (CO2),tends to ban the use of carbon-based fossil energy. This leads to intense research on alternative sources of energy. One of the most promising is hydrogen, but it rises questions in terms of safety and control that need to be clarified in order to use it in domestic, transportation and industrial processes (…)fluides The scientific consensus on the necessity to reduce the greenhouse gases, like carbon dioxide (CO2),tends to ban the use of carbon-based fossil energy. This leads to intense research on alternative sources of energy. One of the most promising is hydrogen, but it rises questions in terms of safety and control that need to be clarified in order to use it in domestic, transportation and industrial processes (…)

Developing experimental technique to measure the microstructure of opaque concentrated suspensions of particles is essential to progress in the understanding of their rheology. The objectives of our project are (1) to develop a novel ultrasound tool to measure the microstructure of concentrated suspensions, and (2) establish the rheology-microstructure relationship in suspensions of red blood cells by using this ultrasound tool and dedicated numerical simulations.

This project addreses the transport and mixing of fluid and inertial particules in a Taylor-Couette cell with permeable cylinders. Analytical expressions for the velocity and pressure fields of laminar and vortical flows have been previously obtained in this configuration and we aim at using them to compute the advection of particules in order to get new insight into their inhomogeneous and unsteady transport. To do so, some open questions such as the forces acting on a particule in the vicinity of a permeable wall must be addressed.

Crystallization is one of the main processes used in industry to produce, purify or separate solid compounds or products. The research project is to develop a continuous crystallization process allowing to produce a compound or a product With fixed properties by membrane contactor. The objective of the specific IMI project also includes the development of a technique to characterize the created crystals by X-ray microtomography and 3D image analyze.