How to set a constant boundary more appropriately?

[XiaoMao]

There are three ways to set a constant boundary in Petrasim,

First, set the boundary cells to fixed state;

Second, set the boundary cells to 1E50 or more

Third, set an extra cell which has large or very large volume,  and then connect the extra cell to boundary cell.

Actually, I am  a beginner for Petrasim, so I am not sure whether these three ways are right.

Please let me know if I make mistake, THANKS!

 

My question is that there is a large lake, and my model domain is the bottom of the lake, so what type should I use when I set the top boundary?

I focus on pressure, saturation and temperature, I do not know what type boundary is more appropriately.

Thank you very much!

 

[Alison]

If all of these variables do not need to vary, then the "Fixed State" option would work fine.  If you need to vary the temperature or pressure of the boundary, then the very large volume option (either set to geometric cells or an extra cell) would be more appropriate.  This way, you could add large amounts of water or heat to the cells to force fluctuations in temperature or pressure.  There is a discussion of time-varying boundaries in the PetraSim manual.

[XiaoMao]

Thanks Alison

[XiaoMao]

On 1/23/2020 at 10:29 AM, Alison said:

If all of these variables do not need to vary, then the "Fixed State" option would work fine.  If you need to vary the temperature or pressure of the boundary, then the very large volume option (either set to geometric cells or an extra cell) would be more appropriate.  This way, you could add large amounts of water or heat to the cells to force fluctuations in temperature or pressure.  There is a discussion of time-varying boundaries in the PetraSim manual.

Can I use a large density , such as 1e50 kg/m3, as a constant boundary?

[Alison]

Yes, for a constant Temperature boundary, you could use a very large density for the boundary cell.