An improved mathematical model for the stability of cylinder rows subject to cross-flow

Abstract

Linearized, quasi-static, fluid force coefficient data obtained from wind tunnel tests are used in an analysis of the fluidelastic stability of a double row of flexible circular cylinders subject to a cross-flow. Although the analysis is quasi-static, frequency dependent terms are obtained in the aerodynamic stiffness and damping matrices; the origin of these terms is twofold: firstly, because of the time lag between flow leaving an upstream row and arriving at a downstream row, which becomes important at low values of the non-dimensional flow velocity Ufd; secondly, because of retardation of the flow approaching the cylinder, which is particularly important when small displacements of the cylinder result in large changes in the fluid force coefficients. This analysis is used to investigate the effects of a number of parameters on the critical flow velocity and the theoretical results are compared with those available in the literature. In general, agreement between theory and experiment is reasonably good, indicating the validity of this analysis.