Abstract:Based on the Timoshenko beam model, the fluid structure coupling vibration characteristics of rotating pipe conveying fluid under free vibration is studied. Considering fluid pressure, gravity and initial axial stress, the partial differential equation of rotating Timoshenko pipe conveying fluid is derived by using Hamilton principle and Euler angle transformation. The partial differential equations of motion are discretized according to Galerkin truncation method. By solving the characteristic equation of the system, the real part and the imaginary part of the first order complex frequency of the pipe conveying fluid are obtained, the real part represents the natural frequency and the imaginary part denotes the energy change. When the fluid velocity is high, it is found that the fourth order and above Galerkin truncation must be considered in order to obtain stable results. By comparing with the EulerBernoulli beam model, the correctness of the results in this paper is verified, and it is found that the Timoshenko beam model is more accurate in the study of short and thick pipes. In addition, the effects of various parameters on the natural frequency and vibration stability of the rotating Timoshenko pipe conveying fluid are studied. The results show that the mass ratio, flow velocity and shear coefficient have significant effects on the stability of fluid structure coupling vibration of Timoshenko pipe conveying fluid. To a certain extent, the moment of inertia, gravity, fluid pressure and initial axial stress also affect the frequency and stability of the pipe conveying fluid. The frequency of the pipe is divided into two values when the rotating speed appears, and the rotating speed does not affect the energy change of the system.