CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Programming & Development

Phase Field Method & Diffuse Interface Modeling in FOAM

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By holger_marschall

Reply
 
LinkBack Thread Tools Display Modes
Old   April 7, 2014, 02:50
Default Phase Field Method & Diffuse Interface Modeling in FOAM
  #1
Senior Member
 
Holger Marschall
Join Date: Mar 2009
Location: Darmstadt, Germany
Posts: 122
Rep Power: 10
holger_marschall is on a distinguished road
Send a message via Skype™ to holger_marschall
Hi FOAMers,

this is just to let you know that Xuan Cai (Karlsruhe Institute of Technology) and me (Center of Smart Interfaces, TU Darmstadt) are working on the implementation of phase field methods / diffuse interface models in FOAM.

In particular, we are aiming at conservative and bounded FV-based methods for the Allen-Cahn and Cahn-Hilliard equations for Direct Numerical Simulations of two-phase flows. The project's topic is on dynamic wetting, where diffuse interface modeling alleviates the known moving contact-line paradox (stress singularity at no-slip walls). However, with phase-field methods, also one could think of other (more exotic) interfacial physics (foaming, crystal growth, etc.), which certainly makes this model class very appealing.

The implementation employs the well-known strategy design pattern. We have chosen the difference of phase volume fractions as an order parameter, such that there are physical bounds within [-1, 1]. The Cahn-Hilliard equation is of fourth order so solution strategy comes into play (segregated/split vs. coupled), which directly bias the boundedness of the order parameter. While the Cahn-Hilliard equation exhibits inherent volume-conservation property, the Allen-Cahn equation needs to be appropriately constrained to this property. However, currently, we are able to obtain a relative volume-error of 1.3E-6 for a spreading droplet after 1.2E-2 seconds.

As an appetizer, allow me to attach some screenshots. At this stage, any comments/hints/ideas on implementation techniques you have heard of and on other test case (currently we examine the 'spreading droplet' and 'rising capillary' cases) are really appreciated...


best regards,
Holger
Attached Images
File Type: png residuals.png (6.8 KB, 67 views)
File Type: png continuityErr.png (6.1 KB, 56 views)
File Type: png extremata.png (4.2 KB, 53 views)
File Type: png phaseVolume.png (5.6 KB, 55 views)
Cyp likes this.
__________________
Holger Marschall
web: http://www.holger-marschall.info
mail: holgermarschall@yahoo.de
holger_marschall is offline   Reply With Quote

Old   April 7, 2014, 03:31
Default
  #2
New Member
 
Xuan Cai
Join Date: Mar 2011
Location: Karlsruhe, Germany
Posts: 9
Rep Power: 6
cfd_explorer is on a distinguished road
Hi FOAMers,

I'd like to join Holger for appreciating your inputs/advices in advance

Best regards,
Xuan
cfd_explorer is offline   Reply With Quote

Old   June 7, 2014, 15:59
Default
  #3
Member
 
Hrushi
Join Date: Jan 2013
Posts: 57
Rep Power: 4
hrushi.397 is on a distinguished road
Hi,

How did you manage to keep the parameter within bounds? How fine is your mesh?

Regards,

Hrushikesh
hrushi.397 is offline   Reply With Quote

Old   August 13, 2014, 11:16
Default
  #4
Senior Member
 
Holger Marschall
Join Date: Mar 2009
Location: Darmstadt, Germany
Posts: 122
Rep Power: 10
holger_marschall is on a distinguished road
Send a message via Skype™ to holger_marschall
Dear all,

just to give you a brief update. We are currently writing a paper describing the conservative Finite Volume discretisation of the Navier-Stokes Allen-Cahn and Cahn-Hilliard equations for two-phase flows. As for some test cases, we opted for dynamic wetting cases.

Please drop me a mail, if you are interested in a preprint. I will keep you posted on the progress.

best regards,
Holger.

PS.:
Quote:
Originally Posted by hrushi.397 View Post
Hi,
How did you manage to keep the parameter within bounds? How fine is your mesh?
Dear Hrushikesh,

this is a natural outcome if you consider coupling in the momentum equation in order to take into account the relative density flux due to diffusion of components. ONLY this allows you to use conservative fluxes! With this, the boundedness property is then found to be consistently enforced (as an inherent property of the phase field transport equations).

The current implementation of this look very clean
Code:
    fvVectorMatrix UEqn
    (
        fvm::ddt(rho, U)
      + fvm::div(rhoPhi, U)
      - fvm::laplacian(mu, U)
      - (fvc::grad(U) & fvc::grad(mu))

      //-HM Coupling term 
      - phaseField.diffRhoPhi(U)

      //- buoyancy and surface tension term
      //- tansferred to pressure equation
    );
The nuts and bolts behind this will be described in the paper. I am also planing a release to Foam-Extend.

Hope this helps,
Holger
__________________
Holger Marschall
web: http://www.holger-marschall.info
mail: holgermarschall@yahoo.de
holger_marschall is offline   Reply With Quote

Old   June 25, 2015, 03:37
Default
  #5
Member
 
Rohith
Join Date: Oct 2012
Location: Bayreuth, Germany
Posts: 45
Rep Power: 4
RaghavendraRohith is on a distinguished road
Hi Holger,

I am trying to model a surface tension and wetting model in a closed capsule geometry using CLSVOF. I have tried different contact angles (Dynamic and static). The complexity of my problem lies in the incompressible nature of phase1 which is solid and wetting occurs post melting of the solid. The velocity is generally very low @ 1e-5 m/s and the also the pressure difference between two phases is also at the range of 30 Pa. Will your model help me in enhancing the nature of wetting in my defined problem?

Please find the attached Jpg.

VG,
Rohith
Attached Images
File Type: jpg wetting.jpg (19.1 KB, 10 views)
RaghavendraRohith is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CGNS converters available mbeaudoin OpenFOAM Meshing & Mesh Conversion 125 July 1, 2015 21:09
Wind turbine simulation Saturn CFX 34 October 16, 2014 05:27
Errors during blockMesh meshing Madeleine P. Vincent OpenFOAM Native Meshers: blockMesh 43 February 18, 2014 03:42
Using starToFoam clo OpenFOAM Other Meshers: ICEM, Star, Ansys, Pointwise, GridPro, Ansa, ... 33 September 26, 2012 04:04
phase field or Cahn-Hilliard method dusky.he Main CFD Forum 3 February 2, 2006 17:43


All times are GMT -4. The time now is 09:58.