RIEMANN PROBLEM FOR A 2 × 2 SYSTEM OF BALANCE LAWS THROUGH APPROXIMATE LIE SYMMETRIES

摘要

In this paper we present an approach, based on the approximate Lie symmetries, for solving a Riemann problem for a 2 × 2 system of balance laws. Focusing the attention on the approximate Lie symmetries which perturbe the homogeneous time and space scaling (admitted by every system of conservation laws), we are able to determine approximate invariant solutions suitable to describe generalized rarefaction waves.