Wake dynamics of a fluttering, elongated bluff body

Flow field measurements using streaming, time-resolved PIV for a rectangular cylinder undergoing flutter are reported. It is shown that the vortices shed from the body do not change their timing significantly compared to statically obtained Strouhal numbers providing evidence contradicting the current conceptual model. Through the phase averaged velocity field, kinetic energy and turbulent kinetic energy (TKE) are shown at points in the cycle where the flow loses the majority of its energy to the structure. The turbulent kinetic energy is observed to change relatively little between low and high amplitude motion revealing that turbulence may only play a second order effect in bluff body flutter. However, the TKE changes significantly within the cycle for the high amplitude case. The energy transfers within the wake, and with the body, are examined.