Wave-Plan Analysis of Unsteady Flow in Closed Conduits

An analytical method for computing unsteady flow conditions in liquid-filled fluid systems is developed. The method, termed the wave plan, incorporates distributed parameter and nonlinear effects including the effects of viscous resistance. The wave plan is essentially a solution synthesized from the effects of incremental step pressure pulses. The pressure pulses are generated because of incremental flow-rate changes that originate in a hydraulic system from a variety of sources, including the mechanical motion of the system structure. The pressure pulses propagate throughout the system at sonic velocity and are partly transmitted and reflected at each discontinuity. The velocity change caused by each pressure pulse is obtained from the Joukowsky relationship. Pressure and velocity time histories at any point in the system are obtained by a timewise summation of the contributions of the incremental pressure pulses passing that point.