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Hi experts,
Could you please explain the significance of nodal boundary condition on a single node only? I have grabbed the following picture from acusolve validation manual.
https://help.altair.com/hwcfdsolvers/acusolve/topics/acusolve/turbulent_flow_through_a_pipe.htm
When I checked the model, I could see that there's fixed pressure only at a single node 8908. How does this work?
The concept of the 'FixedPressureNode' typically applies to cases where there are no other pressure boundary conditions - and is used to set a base pressure. For a case with an inlet and outlet - the outlet is typically set as outflow BC with a specified pressure. That sets all other pressures in the solution relative to that pressure at the outflow boundary. In internal flows (no inlet/outlet) there is no pressure boundary condition, so the resultant pressures can 'vary' with no relation to previous time steps / iterations. One would still get the same pressure difference, but the values could vary. That single node with a fixed pressure helps ground the pressure to a given level. One would normally want to set that in a location where there is not much action in the flow. This is not so important in a steady-state case, but can be quite important in a transient as all the time steps should be related.
Hello Prabin,
I would suggest searching SimLab Help (F1 key) for more information regarding this tool. This is a screenshot directly taken from there.
I suspect this option is available in cases like having already some results and you wish to map them into your existing solution. Of course, other applications as well.
I hope this helps.
Kindly,
Ioannis Makris
