Direct methods for consistent initialization of DAE systems

Rigorous techniques for consistent initialization of differential-algebraic systems (DAEs) are in general difficult to apply. Even worse, since initialization algorithms generally require the solution of a set of non-linear algebraic equations, they may not even converge. Hence, simpler approaches for initialization are of considerable interest in the numerical implementation of DAE models. In this contribution, it is proposed a simple and effective initialization technique. which is based on the assumption that the dynamic response of a mathematical model may be approximated by the response to discontinuous perturbations of a similar system, originally in steady state. Determining the analogous system and smoothening adequately those perturbations are the key aspects for the consistent initialization of the DAEs involved. The technique presented has been tested in several examples, always yielding encouraging results. (C) 2001 Elsevier Science Ltd. All rights reserved.