symetry B.C>
Hi
I am simulating a free jet using Euler equations in the rz plane. What are the boundary conditions for the symmetry plane and how do I implement it numerically? Cheers Shuo 
Re: symetry B.C>
No mass flow across the Z axis.

Re: symetry B.C>
what about the density and pressure?

Re: symetry B.C>
No jumps, there is no mass crossing the symmetry plane, also be carefull, no mass crossing means the normal component of the velocity vector is equal to zero, but the parallel componet is not. you can check the Peric or the Versteeg & Malalasekra books for full details. Good Luck.

Re: symetry B.C>
If I understood correctly you are using cylindrical symmetry. Write the equations in rztheta coordinates and set all thetaderivatives and thetavelocity to zero. You will get an equation that looks almost like the 2d equations but with some source terms.

Re: symetry B.C>
It is similar to the rigid wall boundary condition.

Re: symetry B.C>
So its something like:
v_0 = 0 u_0 = u_1 P_0 = P_1 rho_0 = rho_1 where u & v are the velocity components in the z and r directions respectively. 0 is the symmetry boundary and 1 is the nearest node. Shuo 
Re: symetry B.C>
In my case where flow is axisymmetric, I set like that. The implementation of axisymmetric flows is very straightforward. The results of my axisymmetric cases were right compared to the analyric solution or experimental data. Good luck!

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