Measure of nonlinearity for hyperbolic distributed parameter systems

It is well known that virtually all processes are nonlinear. For analysis and control, it is important to understand the process nonlinearity. In this paper, we introduce a measure of steady-state nonlinearity for processes modeled by partial differential equations. Drawing from results for lumped parameter systems, the nonlinearity measure is based on the local geometry of the steady-state map. Tangential and normal components of the curvature of the steady-state map are used to quantify the process nonlinearity. Application of the measure of nonlinearity is shown for a plug-flow chemical reactor with heat exchanger.