How to change cellzone during simulation?

nuttita · September 29, 2018, 11:45

Hi, I’m simulating porous media flows using porousInterFoam in OF 2.3. I created porous zone in blockMesh for flows through static porous medium and it works fine. However, I need to work with deforming medium. That means the shape of the porous zone changes. Hence, the cellzone needs to be changed during simulation. Does anyone know how to do this? Thank you.

Santiago · September 29, 2018, 12:07

Is it the domain that changes, or you choose a different porous region everytime?

nuttita · September 29, 2018, 16:18

Santiago, thank you for your reply.

The domain doesn't change. Only the porous region in the domain changes every time step. The change is based on a computed field variable alpha.

if alpha = 1 -->> porous region
else non-porous region

This alpha is obtained from another solver that is coupled with porousInterFoam.

Santiago · September 29, 2018, 16:23

Is the porous region adding some source/sink of some kind?

nuttita · September 29, 2018, 17:30

Yes, it’s the Darcy-Forchheimer sink term added to the Navier-Stokes equation. This term is active only in the porous region.

hk318i · September 30, 2018, 10:31

Hello,

There are few ways to solve this problem but it depends on your implementation.

Of course you can create a cellSet each time step and apply the source term for these specific set.

It could cause issues in parallel.

Extra computation time to select those cells.

An example maybe found in topSet, adaptive dynamic mesh ....

2. Don't use cellSet at all, calculate the source term as a function of alpha for each grid cell. Of you kind of if condition if it needed.

Probably there are other solution but all depend on your current code and what features you need in the future.

Best wishes,
Hassan

nuttita · September 30, 2018, 13:43

Dear Hassan,

Thank you for your suggestion.

Nuttita

September 29, 2018, 11:45	How to change cellzone during simulation?	#1
nuttita New Member Nuttita Pophet Join Date: Oct 2016 Location: Mississippi, USA Posts: 10 Rep Power: 10	Hi, I’m simulating porous media flows using porousInterFoam in OF 2.3. I created porous zone in blockMesh for flows through static porous medium and it works fine. However, I need to work with deforming medium. That means the shape of the porous zone changes. Hence, the cellzone needs to be changed during simulation. Does anyone know how to do this? Thank you.

September 30, 2018, 10:31		#6
hk318i Senior Member Hassan Kassem Join Date: May 2010 Location: Germany Posts: 242 Rep Power: 18	Hello, There are few ways to solve this problem but it depends on your implementation. Of course you can create a cellSet each time step and apply the source term for these specific set. It could cause issues in parallel. Extra computation time to select those cells. An example maybe found in topSet, adaptive dynamic mesh .... 2. Don't use cellSet at all, calculate the source term as a function of alpha for each grid cell. Of you kind of if condition if it needed. Probably there are other solution but all depend on your current code and what features you need in the future. Best wishes, Hassan __________________ @HIKassem \| HassanKassem.me

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September 29, 2018, 12:07		#2
Santiago Senior Member Santiago Lopez Castano Join Date: Nov 2012 Posts: 354 Rep Power: 16	Is it the domain that changes, or you choose a different porous region everytime?

September 29, 2018, 16:18		#3
nuttita New Member Nuttita Pophet Join Date: Oct 2016 Location: Mississippi, USA Posts: 10 Rep Power: 10	Santiago, thank you for your reply. The domain doesn't change. Only the porous region in the domain changes every time step. The change is based on a computed field variable alpha. if alpha = 1 -->> porous region else non-porous region This alpha is obtained from another solver that is coupled with porousInterFoam.

September 29, 2018, 16:23		#4
Santiago Senior Member Santiago Lopez Castano Join Date: Nov 2012 Posts: 354 Rep Power: 16	Is the porous region adding some source/sink of some kind?

September 29, 2018, 17:30		#5
nuttita New Member Nuttita Pophet Join Date: Oct 2016 Location: Mississippi, USA Posts: 10 Rep Power: 10	Yes, it’s the Darcy-Forchheimer sink term added to the Navier-Stokes equation. This term is active only in the porous region.

September 30, 2018, 13:43		#7
nuttita New Member Nuttita Pophet Join Date: Oct 2016 Location: Mississippi, USA Posts: 10 Rep Power: 10	Dear Hassan, Thank you for your suggestion. Nuttita