Ventilation of flexible surface-piercing foils
Back in 2021, we conducted a series of experiments to study the ventilation of flexible struts. The experimental campaign was led by Zac Valles and advised by Professor Yin Lu Young. These experiments took place in the University of Michigan Marine Hydrodynamics Laboratory in the towing tank.
Ventilation is a multiphase flow phenomena that typically occurs on lifting surfaces operating near or piercing the free surface (i.e., the air-sea interface). Ventilation incepts when a lifting surface generates sufficient suction force to draw down and entrain noncondensable gas (such as air). The suction pressure on the surface must be below that of the impinging gas. A gaseous cavity forms and will persist if there is a continuous path to the source of gas. Interested readers are encouraged to check out the Applied Mechanics Review paper for a comprehensive discussion of the physics.
Ventilation of strut with external perturbation (wire). Submerged aspect ratio of 2
Ventilation of strut in regular waves. Submerged aspect ratio of 1