[Waggy]

Hi,
I'm new in OpenFOAM and I'm trying to simulate injection of helium into surrounding air (N2/O2/H2O = 0.77/0.225/0.005) with surface (wall) which is located at distance 3 cm from the helium's outlet and perpendicular to the helium's flow.

Firstly, I simulated helium ejecting into air without the wall. In order to do that I used reactingFoam without combustion and chemical reactions.

But I don't know what kind of boundary condition should I use then I want to add the wall. I want the helium's flow to flow along the wall, so I should make normal component of the flow's speed equal zero.

How to do that?