Study of Flow Behavior in a Vibrating Pipe on Offshore Platform

The purpose of this paper is to study flow behavior in a vibrating pipe on offshore platform. The mathematical model of unsteady, incompressible, viscous flow in a vibrating pipe is established according to the basic theory of oscillating fluid mechanics. The governing equations of flow are decomposed into a system for steady flow and another for flow oscillation, with the equations of the differential coefficients of flow parameters solved by using the parametric polynomial method. Velocity and pressure distributions are obtained for different flow conditions. Numerical results indicate that the flow behavior in the vibrating pipe on offshore platform is strongly affected by fluid properties and the pipe structure. A good agreement is obtained when comparing the results with the variational solution in constant cross-section, which shows that the method proposed in this work is effective for studying flow behavior in a vibrating pipe on offshore platform.

The Oscillating Fluid Mechanics Method (OFMM) for Studying Oil Film Oscillation and Dynamic Characteristics of Journal Bearings

A new method to study oil film oscillation and to determine the unstable rotational speed and rotordynamic coefficients of bearings is presented. Differences between the new method called the Oscillating Fluid Mechanics Method (OFMM) and the previous method (quasi-steady state method) are discussed. Insufficiencies of the previous method are analyzed. The theory and calculational procedure of OFMM are given. Calculated results show that this new method provides significantly improved predictions.