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Old   December 1, 2013, 14:27
Default closed tank and dynamic mesh
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Tobias Holzmann
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Hi all,

I worked with rhoPimpleDyMFoam some times in non closed cases but now I have a closed volumina. Therefor I got "pcorr" step to 1000 iterations every time.

To check if this occure with closed volume cases I changed the tutorial case in the rhoPimpleDyMFoam so that there is no inlet and outlet anymore.

Its the same result. pcorr blows up:
Code:
solidBodyMotionFunctions::rotatingMotion::transformation(): Time = 0.0152941 transformation: ((0 0 0) (0.981781 (0 0 0.190014)))
AMI: Creating addressing and weights between 10944 source faces and 10944 target faces
AMI: Patch source weights min/max/average = 0.945398, 1.00512, 0.999941
AMI: Patch target weights min/max/average = 0.951965, 1.00398, 0.999942
GAMG:  Solving for pcorr, Initial residual = 0.999999, Final residual = 20.8413, No Iterations 1000
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
Is there any solution?
Regards
Tobi


PS: @admin - if its possible the title can be changed into "closed volume and dynamic mesh"
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Old   December 2, 2013, 07:30
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Hi all,

I tested my case yesterday again with a few outer faces used to be an atmosphere.

Therefor p is totalPressure and U is an pressureInletOutletVelocity. With this Addition the Simulation is running stable and fast.

pcorr is normal with a few iterations 5 - 20.


But I am still interested why pcorr blows up in closed volume cases.
Maybe I should have a look at the equations
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Old   December 8, 2013, 04:25
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Hi Tobias,

It sounds to me, as if the compressibility of the fluid is not taken into consideration by the solver/pcorr loop. You probably changed the total volume of the box, and then pcorr has a problem in putting the excess volume somewhere.

A suggestion for checking this could be as follows:

1. Set up a simple cavity test.
2a. Move the left and right boundaries with the same velocity.
2b. Move the left and right boundaries with different velocities.

Case 2a should be successful, because the total volume remains constant, and 2b should fail.

Good luck,

Niels
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