fluid mechanics

In order to model effects of automated treatment of respiratory physiotherapy with focused pulses, we study deformation of an elastic material under oscillating constraints on its boundaries. Moreover the system is linked to a symmetrical and dichotomous tree built as series of cylinders, idealizing bronchial tree. To do so, under infinitesimal strain theory, we consider that a change a volume on an area of the material creates airflow. Then we force it to flow in the tree and to go through hydrodynamic resistance. This coupling adds friction to the system and gives information on total airflow created at the top of the tree, i.e. at the mouth, under pressure on boundaries.

Wave turbulence occurs in various domains of physics (plasma physics, elasticity, or fluid mechanics) but is far to be completely understood, notably for ocean surface waves. By using a large-diameter centrifuge, we are able to tune the gravity field up to 20 times the Earth acceleration. This new technique then allows us to report the first observation of gravity wave turbulence on the surface of a fluid in hyper-gravity environment. This is also a unique solution to significantly expands the inertial range of gravity wave turbulence in laboratory. Wave turbulence properties are then reported as function of the gravity level, and we show that the usual energy transfer by nonlinear wave interactions are modified by large-scale container modes.