[dasith0001]

Hi Foamers,

I've worked a bit with chtMultiRegionFoam but I have no experience on 'moving objects'.

I have a very simple case, a solid component submerged in a fluid.

Now, I have two questions;

Q1 - Can I move this object, say to only in z-direction in this fluid domain. if yes, what would be the closest tutorial I should be looking at ?

Q2 - Can I make this object disappear at a time and replace the void with the fluid ? If yes, could you direct me to a starting point.

What would be the easy thing to do between Q1 and Q2 if these are possible at all.

I would highly appreciate your suggestions.
Thank you

[Yann]

Hello,

As far as I know, chtMultiRegionFoam does not support dynamic meshes so I don't think it's possible to move an object with this solver.

Regards,
Yann

[dasith0001]

Hi Yann,

Thank you for your reply, that's what I was being afraid of. I think you are right, https://bugs.openfoam.org/view.php?id=3499

Any ideas to work around this ?

Cheers,
Dasith

[LongGe]

chtMultiRegionFoam does not support dymamicMesh. However, you can Q1 you want by coupling buoyantPimpleFoam and solidFoam which supports dynamicMesh. A sample is in tutorials/multiphase/compressibleInterFoam/laminar/waterCooler. However, I believe you can do simple motions like a solid rotating rigidly, but if the solid is a complex motion, you would have a hard time setting it up. Also, it is unknown whether a heat flux at the fluid-solid interface can be calculated correctly when the solid is in motion.

Note that the sample case given here is a case where the solid is stationary, and you would need to rewrite a solid side dictionaries to move.


Finally, I have used this technique to do cooling analysis of rotating solids.

[dasith0001]

Hi Tatsuya,

Thank you for the input, I will have a look into it

Dasith

[LongGe]

Hello Dasith

This movie is a coupled analysis of VOF + rotating solids. I hope it will be helpful.
https://drive.google.com/file/d/1y4m...U_mDGFVtO/view

LongGe

[dasith0001]

Hi foarmers,

Thank you for all the inputs.

I found the easiest way to block and release a flow in a channel.
I am simply using ''explicitPorositySource'' in the fluid region with high resistance values of D when I want to block the flow and vice versa when I want the flow to go freely.

Problem now is the solver becomes so unstable (crashes ) when I suddenly change the 'D' value from 1e20 to 0. Any ideas resolving the issue?

Thank you
Dasith

[LongGe]

Hello

How about "ACMI patch scaling"?
https://www.openfoam.com/news/main-n...s-acmi-scaling

[dasith0001]

Originally Posted by LongGe

Hello

How about "ACMI patch scaling"?
https://www.openfoam.com/news/main-n...s-acmi-scaling

Thank you for your quick reply, but I am not sure if it is available in chtMultiRegionFoam. After some wrestling I thought got it running but it gives this error

PHP Code:

--> FOAM FATAL IO ERROR:
Unknown patchField type cyclicACMI for patch type genericPatch

Valid patchField types are :

113
(
MarshakRadiation
MarshakRadiationFixedTemperature
advective
calculated
codedFixedValue
codedMixed
compressible::alphatJayatillekeWallFunction
compressible::alphatWallFunction
compressible::thermalBaffle1D<eConstSolidThermoPhysics>
compressible::thermalBaffle1D<ePowerSolidThermoPhysics>
compressible::turbulentTemperatureCoupledBaffleMixed
compressible::turbulentTemperatureRadCoupledMixed
convectiveHeatTransfer
cyclic
cyclicAMI
cyclicSlip
directionMixed
empty
energyJump
energyJumpAMI
entrainmentPressure
epsilonWallFunction
externalCoupled
externalCoupledTemperature
externalWallHeatFluxTemperature
extrapolatedCalculated
fWallFunction
fanPressure 


Any ideas ? I can attached the case file if it helps
Thanks