A transient flow analysis of a longitudinal vibration in a liquid rocket engine propellent feed system and its supporting structural framework is described, together with supporting experimental tests. Nonlinear friction losses are used in the partial differential equations of continuity and momentum describing the unsteady flow. These equations are solved by the methods of characteristics and placed in form suitable for digital computation. The turbopump steady-state characteristic curves are used to find the transient pressure rise across the pump, and the effects of pump inlet cavitation are estimated from experimental data.