A numerical study of an inline oscillating cylinder in a free stream

Justin S. Leontini (1) , David Lo Jacono (1, 2) , Mark C. Thompson (1)

1 Fluids Laboratory for Aeronautical and Industrial Research - FLAIR (Victoria, Australia)
2 IMFT - Institut de mécanique des fluides de Toulouse

Simulations of a cylinder undergoing externally controlled sinusoidal oscillations in the free stream direction have been performed. The frequency of oscillation was kept equal to the vortex shedding frequency from a fixed cylinder, while the amplitude of oscillation was varied, and the response of the flow measured. With varying amplitude, a rich series of dynamic responses was recorded. With increasing amplitude, these states included wakes similar to the Kármán vortex street, quasiperiodic oscillations interleaved with regions of synchronized periodicity (periodic on multiple oscillation cycles), a period-doubled state and chaotic oscillations. It is hypothesized that, for low to moderate amplitudes, the wake dynamics are controlled by vortex shedding at a global frequency, modified by the oscillation. This vortex shedding is frequency modulated by the driven oscillation and amplitude modulated by vortex interaction. Data are presented to support this hypothesis.

Mots clés: Pattern formation; Vortex shedding; Vortex streets

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Justin S. Leontini, David Lo Jacono, Mark C. Thompson. A numerical study of an inline oscillating cylinder in a free stream. Journal of Fluid Mechanics, 2011, vol. 688, pp. 551-568. ⟨hal-00959379⟩