抄録
The issue on outflow boundary conditions (OBCs) is very important in the numerical simulation of incompressible viscous flows. We consider a Sommerfeld radiation condition (SRC) from points of view : one is an analogy between the SRC and Taylor's hypothesis for large-scale vortex structures, and the other is consistency between the SRC and global mass conservation for primitive variables formulation. A new SRC is proposed, in which the convection velocity of the SRC is determined by an arithmetic mean of the maximum normal velocity and minimum normal velocity at the outflow boundary. Our new condition is tested in a numerical simulation using the finite difference method for the problem of Lamb dipole convection in a uniform flow, and its result is compared with the results obtained by adopting three SRCs. Our new condition automatically satisfies the global mass conservation and it gives a more accurate prediction than the old ones.
