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how to initialize pressure field with known value

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Old   September 18, 2018, 09:18
Default how to initialize pressure field with known value
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Tanakorn
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Hi everone,
I'm simulating compressible flow past cylinder but it has some issue with wave reflection at the boundary (https://ibb.co/nuL7CK) so I want to initialize my initial pressure filed with pressure mean value from my old simulation (https://ibb.co/kLXnCK).
I simply tried replacing p file in directory 0/p with my p mean file but result is still not want I want (https://ibb.co/nPQAzz). How do I fix that? And is there any boundary condition that can absorb wave at inlet?
Here's link to my files pmean(https://we.tl/t-11sqSoCI4D), p in directory 0 (https://we.tl/t-mVtP4pOpNp)

Thanks a lot,
Tanakorn
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Old   September 18, 2018, 15:37
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Peter Hess
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Hello!

I think you are searching the mapFields utility!

https://openfoam.org/release/2-3-0/pre-processing/

A good example could be found here:

OF6.0--> /tutorials/incompressible/pimpleFoam/RAS/wingMotion/

Regards

Peter
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Old   September 18, 2018, 19:35
Default Copy and mapFields
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Peter Brady
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Hi Tanakorn,


As Peter Hess has already mentioned mapFields is probably your best bet here.


I regularly also use the copy method you first tried when I'm starting up cavitation simulations but the caveat is that your grids must be identical and the physics the same. Even then there can be some start up errors that take a few iterative cycles to dissipate.


So for my cavitation simulations my workflow is:
  1. single phase simulation on a very low resolution grid to get a velocity field
  2. copy that velocity field to 0 folder for a cavitation simulation to get a velocity and pressure field.
  3. mapFields up from the results in (2) to run the simulation I'm really interested in
Hope that helps,
-pete
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Old   September 19, 2018, 04:52
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Tanakorn
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Thanks for replying guys! I'll look forward to it.
Tanakorn
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