Urgent question for B.C.
 

Sorry you all. I am solving 2-D axi-symmetric flow with the azimuth directional symmetry. That is, I am solving Euler equations for r and z direction. So the geometric source term is divided by 1/r. To reflect symmetric B.C. along z-direction(axial direction), I applied that u(r direction vel.) is zero and the gradient of axial velocity dv/dr is zero. However, it has not worked well with unphysical reflection from the symmetry axis. If anyone had similar ones, please advice me how to properly impose the axi-symmetric B.C for the case where problems are independent on azimuth direction. Thanks a lot.