A liquid/Gas simulation with Comsol Multiphysics

[Comsol_STKM]

Dear Friends !

I would really need Your help. I am currently simulating the temporal development of an interface between liquid and gas, by using Comsol Multiphysics.

The problem can be simplified in terms of a rotating central liquid pick up (a small rotating cylinder endowed with an internal Archimedean screw), which rotates inside a bigger vertical cylinder. 30% of this cylinder is full of liquid, the upper part is full of gas.

I have tried to solve the problem in this term:

1. Two phase flow, laminar, level set (chns) + Moving Mesh (ALE).

2. BOUNDARY CONDITIONS for Two phase Flow Laminar level Set:

For internal rotating walls : no_slip_CW

For the External walls of the shell: No slip

For the interface: Initial interface

Stabilisation method: (GLS)


3. Subdomain SETTING for the moving mesh:

FREE DISPLACEMENT

BOUNDARY CONDITIONS TO PREDICT THE ROTATION OF THE MESH:

ROTATE CW: Internal rotating Structure;

FIXED: External Shell


THIS IS THE ERROR I GOT:

Error: 7300
Pointwise constraints for time-derivatives are not supported.


Can somebody help me ?

Thank You, in advance !
Christiano

 

[Nick Bruno]

I would say its the boundary conditions of your moving mesh. since the walls are no slip internally, do you have it properly coupled? Double check your vairables in your expressions as well, you may be using one that is in the incorrect frame.

http://comsol.com/support/knowledgebase/970/

use chp 16 in ur modeling guide

 

[Comsol_STKM]

Thanx, Bruno

 

[superguridi]

Hi, I´m working right now with COMSOL as a part of a school project at my collegue. I'd like to know if you were able to solve your problem related to moving mesh and two phases.

I´m trying to simulate the churning effect of oil for a single gear inside a box, but I check some of boundary conditions are similar to the ones that I´m using... if you can give a little help of how you solve your problem it will be awesome...

Regards,

Jesus