“…The governing equations for many mechanical problems involving fluids are hyperbolic conservation laws with singular sources. For example, surface tension [18,26], evaporation [15][16][17], phase transition [25,32,33,40,42,43] and condensation [11] at the interface of multiphase flows are formulated by singular sources. Geometric constraints on irregular domains can also 1 INTRODUCTION lead to the generation of singular sources in simplified governing equations, such as the shallow water equations with discontinuous river beds [19,35,39] and the governing equations of nozzle flow with discontinuous cross-section [13,44].…”