Nonlinear dynamics of a fluid-conveying pipe under the combined action of cross-flow and top-end excitations

摘要: Abstract We report a theoretical investigation of an elastic and slender fluid-conveying pipe with top-end excitation subjected to uniform cross flows. Considering the mean drag force time varying vortex-induced lift which is modeled using nonlinear van der Pol oscillator, partial differential equations motion coupled fluid-structure system are constructed simplified reduced-order model through Galerkin-type discretization. By virtue quasi-static displacement conditions, characteristics vibration evaluated for first two lock-in modes. The results show that can increase amplitude when cross-flow speed out regions. When within region, however, oscillation causes transition between quasi-periodic periodic in responses pipe, significantly reducing or increasing amplitudes depending on acceleration frequency. This finding has important guidance suppressing vibrations by balancing internal fluid velocity excitation.