Bifurcations and chaotic motions of a curved pipe conveying fluid with nonlinear constraints

This paper investigates the bifurcations and chaotic motions of a fluid-conveying curved pipe restrained with nonlinear constraints. The nonlinear equation of motion for the curved pipe is derived by forces equilibrium on microelement of the system under consideration. Depending on the nonlinear equation of motion and the corresponding boundary conditions for the curved pipe, the DQM (differential quadrature method) is introduced to formulate the discrete forms of the equation of motion for the system, which is then solved by numerical methods. Calculations of phase-plane portraits, time history diagrams, PS (Power Spectrum) diagrams, bifurcation diagrams and Poincaré maps of the oscillations establish clearly the existence of the chaotic motions. In addition, the result shows the route to chaos for the pipe is via period-doubling bifurcations, which is affected definitively by several parameters of the system.