Opening of a wall-mounted leaflet by a single flow pulse

Abstract

The opening of a leaflet by one flow pulsation is studied here in an ideal system made of a rigid door, initially vertical, mounted on a horizontal wall. The dependence of the fluid-structure interaction on the leaflet inertia and flow parameters has been analyzed. The system has been solved by numerical integration of the Navier-Stokes equations coupled with the body dynamics. The behavior of the movable leaflet and resulting vortex formation has been conditioned through the range of Strouhal numbers and body inertia. When inertia is relatively large, the flow pulsation is unable to significantly move the leaflet. When inertia is relatively low, the degree of opening smoothly increases with lowering the Strouhal number (that corresponds, for example, to either a longer pulsation period or a higher flow velocity). The analysis also demonstrated the existence of a critical intermediate range where the body opens completely and impacts onto the lower wall at high speed.