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Unphysical pressure field in LES PitzDaily tutorial case

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Old   May 31, 2017, 21:49
Default Unphysical pressure field in LES PitzDaily tutorial case
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Jeremy
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Hi Openfoamers,

I was looking into the LES PitzDaily tutorial case(tutorials/incompressible/pisoFoam/les/pitzDaily) and found the pressure result is a terrible disaster: the whole pressure field is fluctuating rapidly and apparently that's not what we expect to have.
I did a raw search and found some threads also had similar confusions. Since a few years have passed, I am posting a new thread to see if there are any solution to this problem in the newest version of Openfoam?

Pitz Daily oodles pressure field problem
Fluctuating Pressure Fields (LES-pisoFoam)
Pressure problem in pitzDaily pisoFoam LES

Thanks a lot!
Jeremy
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Old   June 1, 2017, 08:09
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Uwe Pilz
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I did not have such effects with simulating the Pitz/Daily geometry, but had similar effects with other cases.

One word before: The pressure is harder to calculate than the velocity because it't calculation is indirect. Therefore the accuracy of the presser is often a problem and with it all values derived form it.

Strong pressure fluctuations point to inducing to much turbulence in the systems. This may be the case if you use a turbulence model which has a tendency to do so, combined with a too large time step / a too large maximal Courant number. The pimpleFoam algorithm is especial prone to that because it tries to predict a solution using a large time step and correct it afterwards. It may be necessary to use real small time steps / maxCo here. The wall time for getting a solution may decrease dramatic if you lessen the time step. And the accuracy gets better,
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Old   June 3, 2017, 05:45
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Santiago Lopez Castano
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Jeremy, post some results, a comparison with other results and a description of the spatiotemporal schemes you used. Otherwise is very difficult to help!

Also the LES configuration is very important

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Old   March 9, 2021, 03:53
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Alberto Artoni
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Hello guys!


Any update?
It seems that the reason is due to the inlet condition, turbulentInlet.



Is there anyway to fix them with a postprocessing?
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