[abhinav.iitb005]

I want to model an annular flow at the inlet of an upward facing pipe. How can I set inlet conditions in a 2D model where 20% of the inlet face is liquid flowing on either side of the wall and 60% is gas flowing. Additionally, the gas velocity is 4 m/s and liquid velocity is 1 m/s. Please refer the image for details. I am using the interFoam solver in OpenFOAM and I believe this should be done by modifying the alpha and U for Inlet Boundary.

[Taataa]

One way would be to split the inlet to two section, and apply the appropriate boundaries accordingly. In the blockMeshDict add the required vertices, blocks, faces and boundary names.

[deepakvil]

Hello, Did you get solution for your trouble, if so, can you list the procedure

[dferrando]

Hello Deepakvil.


I am not the person who opened the thread but the second answer is right. You should create 2 separated boundary patches on the blockMeshDict or doing it with the createPatch tool (which is a bit more complicated).


So, in the case that the OP shared, you should create 3 block, left to right, liquid/gas/liquid block. When you define the boundary patches, you have to create 2 patches:
Liquid_Inlet: side faces of the picture
Gas_Inlet: Middle face



If you have a more specific problem just post it here with more information.

[deepakvil]

Hello dferrando,


Thanks for the prompt reply. My problem is different from the original problem listed at the start of the thread. I am doing a air-water flow in a channel. Its a 2D, axi-symmetric with interFOAM. For 0 to R', its air and R' to R, its water. R is channel radius. I want to fix this ratio of phases at the inlet throughout my simulation. I also want to specify velocities for both of them. The idea is based on the ratio & velocity at the inlet, air bubbles will form as part of the simulation.



I tried setfields with a hemisphere at the inlet as shown in attachment. However the inlet ratio is not a constant through simulation. Also i couldn't specify individual velocities.



I am confused about how to implement this inlet BC. Can i have a single block and implement the Inlet BC or I split into two. How do i update/specify the phases(air & water) in the u file and alpha.water.orig in 0 folder?

[deepakvil]

Hello dferrando,


I split my blocks into two. One on top of the other.

I am successful in defining the two separate velocities at two inlet face created.


What is troubling me defining the phases at the inlet? I need help here.I want to fix one phase for each inlet face. How to i define this in alpha.water.orig file. I use interFoam.

[mani4be]

Originally Posted by deepakvil

Hello dferrando,


I split my blocks into two. One on top of the other.

I am successful in defining the two separate velocities at two inlet face created.


What is troubling me defining the phases at the inlet? I need help here.I want to fix one phase for each inlet face. How to i define this in alpha.water.orig file. I use interFoam.

Hi deepakvil,
how do initialize the two different velocity in single boundary?