  The DFLU numerical flux was introduced in order to solve hyperbolic scalar
conservation laws with a flux function discontinuous in space. We show how this
flux can be used to solve certain class of systems of conservation laws such as
systems modeling polymer flooding in oil reservoir engineering. Furthermore,
these results are extended to the case where the flux function is discontinuous
in the space variable. Such a situation arises for example while dealing with
oil reservoirs which are heterogeneous. Numerical experiments are presented to
illustrate the efficiency of this new scheme compared to other standard schemes
like upstream mobility, Lax-Friedrichs and Force schemes.
