An Implementation of the Method of Characteristics Using ACSL Software

Abstract

The simulation of gas flows in a reciprocating engine requires solution of the equations of gas dynamics because of the pressure waves in the manifolds, for example. The method of characteristics provides a means for solving hyperbolic partial differential equations. We propose in this paper a new way to implement this using ACSL software. After presenting an outline of the method of characteristics and ACSL software, we present a program to solve a simple case: a pressurized pipe with a gradually opening valve. The state event mechanism allows the boundary conditions and the intersections of the characteristics emitted from both ends of the pipe to be dealt with precisely while the solution of the differential equations is realized in a continuous fashion.