Spontaneous Symmetry Breaking of a Hinged Flapping Filament Generates Lift
Nordita Astrophysics seminars
Wednesday 24 October 2012
to 13:30 at
Shervin Bagheri (Linné Flow Centre KTH Mechanics, Stockholm)
Elastic filamentous structures found on swimming and flying organisms are versatile in function, rendering their precise contribution to locomotion difficult to assess. In this talk, we discuss how a single passive filament hinged on the rear of a bluff body placed in a stream can generate a net lift force without increasing the mean drag force on the body. This is a consequence of spontaneous symmetry breaking in the filament’s flapping dynamics. The phenomenon is related to a resonance between the frequency associated to the von-K ́arman vortex street developing behind the bluff body and the natural frequency of the free bending vibrations of the filament. Moreover, the immersed boundary method employed to numerical solve the fluid-structure interaction will be discussed.