Noisy inflows cause a shedding-mode switching in flow past an oscillating cylinder.

Vortex streets formed behind oscillating bluff bodies consist of arrays of groups of two, three, or four vortices classified as 2S, P+S, and 2P shedding modes, respectively. The prevailing dominant mode depends primarily on the amplitude and the frequency of the oscillation and on the Reynolds number. We investigate the effect of noise at the inflow on the stability of these vortex modes in laminar flow past a circular cylinder. We employ stochastic simulations based on a new polynomial chaos method to study the shedding-mode switching from a P+S pattern to a 2S mode in the presence of noise.

[1]  O. Griffin,et al.  The vortex-street wakes of vibrating cylinders , 1974, Journal of Fluid Mechanics.

[2]  Donald Rockwell,et al.  Flow structure from an oscillating cylinder Part 1. Mechanisms of phase shift and recovery in the near wake , 1988, Journal of Fluid Mechanics.

[3]  C. Williamson,et al.  Modes of vortex formation and frequency response of a freely vibrating cylinder , 2000, Journal of Fluid Mechanics.

[4]  Dongbin Xiu,et al.  The Wiener-Askey Polynomial Chaos for Stochastic Differential Equations , 2002, SIAM J. Sci. Comput..

[5]  George Em Karniadakis,et al.  Predictability and uncertainty in CFD , 2003 .

[6]  N. Wiener.  The Homogeneous Chaos , 1938 .

[7]  G. Karniadakis,et al.  Spectral/hp Element Methods for CFD , 1999 .

[8]  D. Rockwell,et al.  FORCES AND WAKE MODES OF AN OSCILLATING CYLINDER , 2001 .

[9]  A. Roshko,et al.  Vortex formation in the wake of an oscillating cylinder , 1988 .

[10]  D. Xiu,et al.  Stochastic Modeling of Flow-Structure Interactions Using Generalized Polynomial Chaos , 2002 .

[11]  G. Karniadakis,et al.  A direct numerical simulation study of flow past a freely vibrating cable , 1997, Journal of Fluid Mechanics.

[12]  P. Steerenberg,et al.  Targeting pathophysiological rhythms: prednisone chronotherapy shows sustained efficacy in rheumatoid arthritis. , 2010, Annals of the rheumatic diseases.

[13]  R. Ghanem,et al.  Stochastic Finite Elements: A Spectral Approach , 1990 .

[14]  George Em Karniadakis,et al.  Dynamics and flow structures in the turbulent wake of rigid and flexible cylinders subject to vortex-induced vibrations , 1999, Journal of Fluid Mechanics.