[namandoshi]

I have already gone through this still not able to understand https://www.sharcnet.ca/Software/Ans.../i5500692.html

Q1. What difference will it make if I give a velocity normal to an area(in +ve direction) inside a domain with inlet, opening or outlet condition
I just need to specify velocity 5m/s normal to that area.

1) opening ask for
velocity
temp (opening/static)
mass fraction

2) Inlet ask for
velocity
temp (Total/static)
mass fraction

3) Outlet ask only
velocity

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Q2. can I define an expression so that for opening and inlet condition temp and mass fraction (which i don't know at that point) is taken automatically whatever value is there?

that is in place of temp i write 'T'
and in place of mass fraction, i write 'Water Ideal Gas.mf'

[ghorrocks]

Q1: What difference will it make? Why not just try them and see for yourself?

Q2: Boundary conditions are of two basic forms: Dirichlet (https://en.wikipedia.org/wiki/Dirich...dary_condition) or Neumann (https://en.wikipedia.org/wiki/Neuman...dary_condition). Dirichlet means the value of the variable is specified at the boundary and Neumann means the gradient of the variable is specified at the boundary. Your question is unclear, so can you state it again using Dirichlet and Neumann boundary conditions?