Physical lumping methods for developing linear reduced models for high speed propulsion systems

A method that allows the development of both high-order large perturbation models and low-order small perturbation models of high-speed propulsion systems is presented. The large perturbation models have a clear nonlinear state space representation as compared with the usual computational fluid dynamics methods. The small perturbation models are easily obtained, given the propulsion system operating point. This modeling approach should be very useful in control system design and essentially parallels that developed by A. Chicatelli and T. T. Hartley (1990)