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Deformation of liquid droplet

Posted Jun 18, 2012, 4:29 p.m. EDT Fluid & Heat, Microfluidics, Studies & Solvers Version 4.4 10 Replies

Chloe Wu
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I am new to COMSOL, so I am referencing a work on deformation of liquid droplet impacting a solid surface. I tried to recreate the same model as that work. But I ran into several problems. As I tracked the steps taken by solver, at a certain time, the volume fraction of liquid would suddenly turn into 0.5 all over the domain. My result just doesn't seem right.

Also, I want to track the contact angle between liquid and solid surface, but I don't know how. Should I set up some new geometry?

Here is the link to the work I am referring to: www.comsol.com/papers/8116/

Attachment is my model. Please take a look at it and show me a right direction. I'm using version 4.3

Thank you!

Attachments:

10 Replies Last Post Oct 6, 2014, 8:49 a.m. EDT
Chloe Wu
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Posted: 1 decade ago Jun 19, 2012, 8:48 a.m. EDT
This is a simple model: 2-D axisymmetric, Laminar Two-Phase Flow, a water droplet falls down onto a solid surface due to gravity. I want to model the deformation process of the droplet after hitting to the ground. But my result is rather than dropping down to the ground and deformting, the droplet would suddenly spread all over the air domain.
This is a simple model: 2-D axisymmetric, Laminar Two-Phase Flow, a water droplet falls down onto a solid surface due to gravity. I want to model the deformation process of the droplet after hitting to the ground. But my result is rather than dropping down to the ground and deformting, the droplet would suddenly spread all over the air domain.
Muhammad Noman Hasan
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Posted: 1 decade ago Aug 22, 2012, 1:20 p.m. EDT
I am also trying to do something similar. there are some difficulties I am facing. I can simulate the impact and the water droplet spreads a little then the solution fails.

I can solve the problem when the droplet is falling from a few millimeter above the surface.

I also what to assign an initial velocity of the droplet but I couldn't can anyone help?

The model is based on COMSOL 3.5
I am also trying to do something similar. there are some difficulties I am facing. I can simulate the impact and the water droplet spreads a little then the solution fails. I can solve the problem when the droplet is falling from a few millimeter above the surface. I also what to assign an initial velocity of the droplet but I couldn't can anyone help? The model is based on COMSOL 3.5
Arthur Shoihet
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Posted: 1 decade ago Oct 3, 2012, 9:56 a.m. EDT
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Shawn.F
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Posted: 1 decade ago Oct 19, 2012, 12:23 p.m. EDT
Hi everybody,

I have the exact same problem. I believe it has to be due to mesh and boundary conditions. I am trying to play with mesh and also implement different BCs.

If you have also found any way to get rid of this problem, I appreciate if you could share it with me.

Regards

Shawn
Hi everybody, I have the exact same problem. I believe it has to be due to mesh and boundary conditions. I am trying to play with mesh and also implement different BCs. If you have also found any way to get rid of this problem, I appreciate if you could share it with me. Regards Shawn
Shawn.F
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Posted: 1 decade ago Oct 19, 2012, 12:26 p.m. EDT

Hi everybody,

I have the exact same problem. I believe it has to be due to mesh and boundary conditions. I am trying to play with mesh and also implement different BCs.

If you have also found any way to get rid of this problem, I appreciate if you could share it with me.

Regards

Shawn
Hi everybody, I have the exact same problem. I believe it has to be due to mesh and boundary conditions. I am trying to play with mesh and also implement different BCs. If you have also found any way to get rid of this problem, I appreciate if you could share it with me. Regards Shawn
Arthur Shoihet
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Posted: 1 decade ago Oct 21, 2012, 12:22 p.m. EDT
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H
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Oct 21, 2012, 2:21 p.m. EDT
Hi

if you change the material you need to check both fluid nodes to set the right material to fluid1, as well as the interface to gas/liquide water air.

Furthermore, with the buble in contact with a surface, and with weting conditions, you have capilary forces that might be greater than the gravity forces, so I would recommend to leave the drop fully "flaoting" not initially in contact with any surface.

and I would use a p=0 point in one of the corner of the outer geometry, not attached to the initial droplet position

By the way, why not set wetting to all walls (wall1, and disable wall2&3) this works for me

Then your mesh is rather coarse, for a thin viscuouity fluid such as air this might be an issue


--
Good luck
Ivar
Hi if you change the material you need to check both fluid nodes to set the right material to fluid1, as well as the interface to gas/liquide water air. Furthermore, with the buble in contact with a surface, and with weting conditions, you have capilary forces that might be greater than the gravity forces, so I would recommend to leave the drop fully "flaoting" not initially in contact with any surface. and I would use a p=0 point in one of the corner of the outer geometry, not attached to the initial droplet position By the way, why not set wetting to all walls (wall1, and disable wall2&3) this works for me Then your mesh is rather coarse, for a thin viscuouity fluid such as air this might be an issue -- Good luck Ivar
Arthur Shoihet
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Posted: 1 decade ago Oct 25, 2012, 4:06 a.m. EDT
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Richard Geist
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Posted: 1 decade ago Nov 18, 2012, 10:11 p.m. EST
Change the transient initialization to phase initialization, due to the two-phase flow and the use of the level set method.

It is running for me at the moment, just waiting for results.
Change the transient initialization to phase initialization, due to the two-phase flow and the use of the level set method. It is running for me at the moment, just waiting for results.
Clare Knock
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Posted: 1 decade ago Oct 6, 2014, 8:49 a.m. EDT
Hello,

I'm also trying to set up a similar problem to the following papers:

www.comsol.com/paper/deformation-behavior-of-a-liquid-droplet-impacting-a-solid-surface-8116

www.comsol.com/paper/solidification-of-a-liquid-metal-droplet-impinging-on-a-cold-surface-1492

I'm new to COMSOL and have a trial of 4.4 for another week, I'd like to see if I can get the problem set up before I buy the software. Can anyone give any advice as to how I can set up a droplet impacting a solid surface in COMSOL?

Thanks,
Raquel
Hello, I'm also trying to set up a similar problem to the following papers: http://www.comsol.com/paper/deformation-behavior-of-a-liquid-droplet-impacting-a-solid-surface-8116 http://www.comsol.com/paper/solidification-of-a-liquid-metal-droplet-impinging-on-a-cold-surface-1492 I'm new to COMSOL and have a trial of 4.4 for another week, I'd like to see if I can get the problem set up before I buy the software. Can anyone give any advice as to how I can set up a droplet impacting a solid surface in COMSOL? Thanks, Raquel

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