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Laminar two phase flow, moving mesh
Posted Apr 10, 2017, 10:06 p.m. EDT Fluid & Heat, Heat Transfer & Phase Change, Mesh 2 Replies
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Hi,
I am going to model a vapor bubble that is growing in the liquid inside a 2D channel. liquid has an inlet velocity that drag the bubble downstream and also bubble is growing due to the mass flux of evaporation that is going to bubble. I am using the "laminar two phase flow moving mesh". I noticed a warning "inverted mesh element " and then it diverges before even the first time step. can anyone help me to fix this?
Thank you in advance.
I am going to model a vapor bubble that is growing in the liquid inside a 2D channel. liquid has an inlet velocity that drag the bubble downstream and also bubble is growing due to the mass flux of evaporation that is going to bubble. I am using the "laminar two phase flow moving mesh". I noticed a warning "inverted mesh element " and then it diverges before even the first time step. can anyone help me to fix this?
Thank you in advance.
2 Replies Last Post Apr 14, 2017, 9:51 p.m. EDT
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Posted:
8 years ago
Meisam,
The best thing is to contact the COMSOL support. However, try the following before you contact them:
- Start your simulation without evaporation/condensation and see if it works.
- Try to use the slowest liquid inlet velocity and ramp it up to your desired velocity.
- Use smaller relative and absolute errors.
- Start your simulation with coarser meshes.
- Use the fully coupled solver with PARDISO method (just according to my experience with this physics). Increase the number of allowed iterations, and update the Jacobean on every iteration. Change the damping factor in newton iteration or set it to automatic Newton rather than constant 1.
- Start your simulation with a very small time range (0,1e-3,1e-2). Then increase the time span (1e-2,0.1,1)
If none of the above get your simulation running, then contact COMSOL support.
Amin,
The best thing is to contact the COMSOL support. However, try the following before you contact them:
- Start your simulation without evaporation/condensation and see if it works.
- Try to use the slowest liquid inlet velocity and ramp it up to your desired velocity.
- Use smaller relative and absolute errors.
- Start your simulation with coarser meshes.
- Use the fully coupled solver with PARDISO method (just according to my experience with this physics). Increase the number of allowed iterations, and update the Jacobean on every iteration. Change the damping factor in newton iteration or set it to automatic Newton rather than constant 1.
- Start your simulation with a very small time range (0,1e-3,1e-2). Then increase the time span (1e-2,0.1,1)
If none of the above get your simulation running, then contact COMSOL support.
Amin,
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Posted:
8 years ago
Thank you for your response Amin,
I tested PARDISO but it is not gonna work well. I think it works well for Level Set not ALE.
I am solving the problem decoupling the energy equation and leaving out the evaporation but i could not get converged.
Thank you again.
I tested PARDISO but it is not gonna work well. I think it works well for Level Set not ALE.
I am solving the problem decoupling the energy equation and leaving out the evaporation but i could not get converged.
Thank you again.