Dynamics of a Pipeline with a Liquid on a Rotating Base

A model of a pipeline that rotates about its longitudinal axis and in which a fluid flows is developed. A nonlinear finite-dimensional dynamic model of a pipeline with fluid is constructed in terms of amplitudes of vibration modes of a resting pipeline with fluid based on a nonlinear model that uses the mixed (Euler–Lagrangian) description of the motion of the elastic and liquid components and accounts for centrifugal forces, internal pressure forces, reactive forces, Coriolis forces, and longitudinal compression. The dependence of the vibration frequencies of the pipeline on the parameters of fluid motion and the angular velocity of the pipeline is studied. The sub- and supercritical ranges are established based on the critical velocities determined. The effect of the pulsation of flow velocities on the dynamical behavior of the pipeline both in sub- and supercritical ranges of fluid velocities is analyzed. It is shown that an increase of fluid velocity (both medium and pulsation components) leads to an increase of the frequencies and amplitudes of pipeline oscillations.