boundary condition definition

[QB-Lin]

What is the difference between the boundary condition: periodic, mass_inflow_outflow, no_slip_wall, slip_wall, symmetric_wall and wall_model.
What is the definition of symmetric_wall
https://exawind.github.io/amr-wind/user/inputs_Boundary_conditions.html

[moprak-nrel]

A lot of these can be found in the documentation in the inputs section and the theory sections. I'm not sure what your application usecase is, but it might be easier to help you figure out what you need there vs a general issue on all the input options.

https://exawind.github.io/amr-wind/user/inputs_Boundary_conditions.html
https://exawind.github.io/amr-wind/theory/theory.html#symmetric-wall-boundary

[QB-Lin]

I am simulating a computational domain like the picture below. This domain is generally built in the commerical cfd software (fluent or STAR-CCM+). But when building this domain in AMR-Wind, the corresponding boundary condition should be carefully set up.

Now for the domain above, my boundary condition is: xlo.type = mass_inflow, xhi.type= pressure_outflow, ylo.type = yhi.type = zhi.type = symmetric_wall, zlo.type= wall_model (Moeng).
I currently simulate the "symmetry" boundary in the ylo, yhi, and zhi plane. I previously use slip_wall. Previously I think symmetric_wall is a wall model that have wall shear stress. But now I think that maybe symmetric_wall is more suitable than slip_wall for a symmetry boundary.

[moprak-nrel]

The symmetry wall condition was designed with a flow like Channel flow in mind where the entire flow is symmetric across the centerline. Looking at your domain, I don't think that a symmetry boundary condition is appropriate for any of the boundaries.

Perhaps you can look through the BCs used in our benchmarks repository for ideas: https://github.com/Exawind/exawind-benchmarks
We generally set zhi as a slip_wall for both ABL and turbine simulations. Ylo/Yhi depends on the application, but it's often periodic or a mass inflow/boundary plane depending on the mean flow direction.