抄録
This paper presents a new formulation to define boundary conditions for compressible Navier-Stokes equations using a skew-symmetric form of the convection terms. The formulation is based on characteristic wave relations and generalized to the Navier-Stokes equations (hereafter referred to as NSCBC). The average of the divergence form and the advection form leads to the skew-symmetric form for NSCBC. Test examples include a vortex in a supersonic flow leaving the computational domain through a non-reflecting outlet and spurious wave reflections in the computational domain using various finite difference methods. The numerical results reveal that the three NSCBC forms are highly compatible. Especially, when the finite difference schemes higher than 6th order are applied, the numerical differences between them are fairly small. This provides a significant step of the skew-symmetric formulation for compressible flow simulations.
