Analysis of Liquid and Structural Transients in Piping by the Method of Characteristics

Abstract

Since liquid-filled piping systems are composed of slender elements, their transient behavior can be described as one-dimensional wave phenomena. Seven wave components are identified: coupled axial compression of liquid and pipe material; coupled transverse shear and bending of the pipe elements in two principal directions; and torsion of the pipe wall. Utilizing the method of characteristics, the combined system of difference equations for pipe elements and the pipe junction boundary conditions comprise a general mathematical tool for predicting the liquid pressure and pipe stress responses to transient excitation of either liquid or piping. The complexity of fluid-structure interaction that can take place is demonstrated.