A FREE LAGRANGE METHOD FOR GAS-DYNAMICS

This paper presents a new Lagrangian approach to the numeric solution of the equations of gas dynamics in two dimensions. This new method, t he signal method, is implemented here as a free Lagrange method using the code FLAME. The signal method is conservative, stable, unsplit, po sitive definite, accurately tracks strong shock fronts with ease, and adapts to and follows complex gas flows for long times. No artificial viscosities are introduced. The implementation is first-order, but pro duces results comparable to modern second-order Eulerian techniques, e ven for problems well-suited to Eulerian computations. For the many ot her problems where Lagrangian methods are superior a relative advantag e is held by the signal method. No special knowledge of the solution i s required in advance, and only local information is used.