Learning Forum

[AnthonyB08]

Hi all,

 

My question is if I set the gas velocity as a negative value, so it can re-enter the domain at the bottom, does the momentum source term need to switch polarity? 

For example if the flow was co-current the momentum conservation would follow as: 

where any sink term implemented, by UDF, is assigned a negative value. So my question is if the direction of the flowing fluid is negative does the entire momentum conservation flip in polarity as well.. making my sink term a positive value? 

[Rob]

I'm not sure what you're asking. The porous media is a resistance to flow, so direction is covered by porous media and speed is then used in the equations. 

If you mean the boundary conditions, you may need to review open channel if you expect the liquid to reach the far end of the domain.