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Does local boundary condition overwrite the global/domain ones?

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Old   September 2, 2014, 04:58
Default Does local boundary condition overwrite the global/domain ones?
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Pavel
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Hello,

I am wondering if the local boundary conditions (e.g. inlet, top, outlet) overwrite the whole domain initial conditions. If the domain's pressure is 1atm and I set hydrostatic pressure for outlet, will the former be added to the latter?

Or if I add 2 inlet conditions (e.g. velocity due to waves and tidal current velocity)...what happens in this case?

Any help is highly appreciated!

Thanks very much!
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Old   September 2, 2014, 08:29
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It will be good to read the documentation

CFX-Solver Theory Guide: Chapter 11: Discretization and Solution Theory | 11.1. Numerical Discretization

The initial conditions are to initialize the control volume values, while the boundary condition are applied at the integration points of the element faces at the boundary of interest. There is not overlap between the values; therefore, nothing to worry about.

Of course, you do not want to initialize the control volume pressure value to say 1MPa while the boundary condition of the integration point next to it is set to 0.01MPa (or 100MPa). It will drive the flow crazy until the solution converges (if it does).

Hope the above helps.
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Old   September 5, 2014, 04:40
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hi Opaque,

Thanks for your answer. This helps
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