Lumped-volume dynamic equations are derived using an energy-state formulation. This technique requires the writing of state functions for kinetic and poten tial energy. A Rayleigh dissipation function accounts for losses in the system. Using these functions, a Lagrangian is formed and the equations of motion for the system are derived. An example of the application of this technique is a model of the free-piston Stirling engine. The model was simplified and pro grammed on an analog computer. Data obtained by simulation compares favorably with experimental data.
