Numerical Analysis of the Instabilities in the Near Wake of a Circular Cylinder at Low Reynolds Numbers
Numerical experiments are described which followed the experimental observation of the production of an oscillatory wake by the insertion of a control rod on the centre line of the near wake at Reynolds numbers, Re, (based on diameter, d) less than the critical Re. The computed values of CL grew exponentially for a range of positions of the control on the wake axis.
Results are presented which show that the driving force at Re < Recrit is small fluctuations in the near wake which convect downstream. Their interaction with the control rod produces oscillations at the control rod which feed back to the cylinder to initiate the exponential growth of CL. At Re > Recrit the exponential growth of CL takes place without a control in the wake. The growth rate as a function of Re is determined and compared with other work.
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- 1.Al-Khafaji, A.A.: Instabilities in the near wake of a circular cylinder at low Reynolds number. Ph.D. thesis, (1989) University of Manchester.Google Scholar