Fluid-Structure Interaction

Fluid-structure interaction refers to a large amount of scientific topics and is present in many industrial applications. Engineers are indeed often faced to problems that cannot be solved by isolating fluid mechanics from solid mechanics. Such problems are said to be coupled and have to be treated as a whole. This generally lead to new phenomena that researchers try to predict and to understand.

At UME, we are interested in the instability of vibrating structures due to a flow. We observe this type of instabilities in many engineering fields, such as civil engineering (vibration of the stays of bridges or the chimneys by strong wind), aeronautics (wing flutter...), biomechanics (vocal folds vibration, snoring due to glottis vibration…), nanotechnologies (sensors). Comprehension of this coupling between flow and structure is also of crucial interest in new scientific topics such as the search for new means of propulsion by bio-imitation (stroke of fish, insects) or energy harvesting from the unstable vibrations of structures.

In particular, we want to predict the critical flow velocities for flutter instability of slender structures in an axial flow and to characterize of the role of various physical parameters (dissipation) and geometry (flow confinement, length). Recently, progresses in the comprehension of unexpected effect of destabilization through addition of damping were obtained. This effect can be attributed to a mechanism of energy transfer between flow and waves which only exists when dissipation is present in the system. Effects of confinement and three-dimensionality of flow on critical flow velocities are also part of our concerns.

We are also interested in the physics of vocal folds. Sound produced by the vocal folds originates from a flow-induced instability. We study experimentally and numerically the vibration of the vocal folds in the phonation regime. We in particular seek to quantify the position of the separation point of the jet at exit of the vocal folds, whose knowledge is crucial in the theoretical models used at present.