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Questions about the inlet/outlet boundary.

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Old   July 23, 2023, 03:14
Default Questions about the inlet/outlet boundary.
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Zhang
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Hi,
Excuse me, I still have some questions about the boundary conditions.
Outlet: If I want a freestream outlet, in my opinion, the back pressure should be 0, but it didn't carry under 0. So can I get a freestream outlet as setting the back pressure as 1? Or should I set the outlet as farfield to get a freestream outlet?
Inlet: Also want a freesteam inlet. In Fluent, I usually set it as pressure-far-field, so is it the same as "MARKER_FAR" in SU2? Or set it as "MARKER_INLET"?

I'm sorry that my English is poor, so the statement of my question may be confusing. Thanks for your patience.
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Old   September 15, 2023, 04:38
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Zach Davis
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Again, this depends on what type of flow you're simulating. For external flows, you typically set all of your outer boundaries to farfield type boundary conditions. For internal subsonic flows, you would typically set the upstream inflow boundary to a subsonic inflow boundary condition type where you specify total pressure and total temperature. For the downstream outflow boundary, you would set it to a subsonic outflow boundary type where you prescribe static pressure (or mass flow rate).
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Old   September 20, 2023, 03:03
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Quote:
Originally Posted by RcktMan77 View Post
Again, this depends on what type of flow you're simulating. For external flows, you typically set all of your outer boundaries to farfield type boundary conditions. For internal subsonic flows, you would typically set the upstream inflow boundary to a subsonic inflow boundary condition type where you specify total pressure and total temperature. For the downstream outflow boundary, you would set it to a subsonic outflow boundary type where you prescribe static pressure (or mass flow rate).
I also have questions about the outlet BC in SU2. For the SWBLI case in V&V in the official site[https://su2code.github.io/vandv/swbli/], the flow is supersonic at the outlet, why the cfg file specify the outlet pressure[https://github.com/su2code/SU2/blob/.../config_sa.cfg]? Usually, the flow downstream at supersonic speed is calculated from upstream, but SU2 does not provide such supersonic outlet boundary condition. In Wind-US configuration file, they specify the downstream pressure to be extrapolated, rather than specify the outlet pressure for the Ma=5 SWBLI hypersonic flow.[https://www.grc.nasa.gov/WWW/wind/va...y02/uns_sa.dat]
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