An Improvement of the Time Delayed Quasi-Steady Model for the Oscillations of Circular Cylinders in Cross-Flow

ISSN： 0889-9746

Source： Journal of Fluids and Structures, Vol.13, Iss.3, 1999-04, pp. : 291-307

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Abstract

This paper is devoted to an improvement of the time-delayed quasi-steady model for the prediction of the movement-induced vibrations of tubes mounted in tandem or in an in-line bundle. The improvement lies in the physical interpretation and calculation of the time lag which is based on measured steady force coefficients. In order to calculate the time lag, a mean convection velocity between cylinders is estimated at each time step. A linear analysis of the present model gives a critical velocity which is in good agreement with an unsteady experiment found in the literature. Moreover, limit-cycle amplitudes are relatively well predicted and show that instability is triggered by the time lag, whereas amplitude is governed by nonlinear aerodynamic damping as for a Van der Pol oscillator.