The Research On Stability And Dynamics Of Cylinders In Axial Flow

In this paper, the stability and dynamics of a cylinder which supported at both ends in the axial flow were studied. The differential equation of motion was introduced for the cylinder in the axial flow, and the equation was discretized with four-mode Ritz-Galerkin method. The evaluation method of the non-zero equilibriums was described, in detail, with the four-mode discretized equation.Through analyzing the eigenvalues of the linear equation, the stability of the zero equilibrium was studied with varying flow velocity (u ). The effect of parameters of the mass ratio(β), friction drag coefficient(εc_f) and flow velocity (u ) on the stability of the non-zero equilibriums was investigated, and the existence region of the non-zero equilibriums and their positions were determined with the varying parameters ofεc f,Γ(axial force) andβ.The frequencies of the clamped-free and towed-free cylinders subjected to the axial flow were calculated using the finite element method, and the effect of some parameters, such asεc_f, f₂(the free-end shape parameter) andβon the frequencies was examined numerically.