A high-order nonconservative approach for hyperbolic equations in fluid dynamics
This work addresses the long-standing problem of obtaining correct solutions from nonconservative formulations, which is useful for fluid dynamics simulations with complex equations of state.
The paper presents a nonconservative numerical approach for hyperbolic equations in fluid dynamics that yields correct weak solutions, overcoming the traditional limitation that nonconservative schemes fail to converge to the right solution. The method produces oscillation-free solutions for the Euler equations with nonlinear equations of state, unlike classical conservative methods.
It is well known, thanks to Lax-Wendroff theorem, that the local conservation of a numerical scheme for a conservative hyperbolic system is a simple and systematic way to guarantee that, if stable, a scheme will provide a sequence of solutions that will converge to a weak solution of the continuous problem. In [1], it is shown that a nonconservative scheme will not provide a good solution. The question of using, nevertheless, a nonconservative formulation of the system and getting the correct solution has been a long-standing debate. In this paper, we show how get a relevant weak solution from a pressure-based formulation of the Euler equations of fluid mechanics. This is useful when dealing with nonlinear equations of state because it is easier to compute the internal energy from the pressure than the opposite. This makes it possible to get oscillation free solutions, contrarily to classical conservative methods. An extension to multiphase flows is also discussed, as well as a multidimensional extension.