How does ANSYS FLUENT model the surface tension in the Eulerian (multi-fluid) model?

- September 4, 2018 at 11:50 am
  
  mohamedh
  Subscriber
  
  I am using ANSYS FLUENT to model a two-phase flow of liquid and gas using the Eulerian model where the surface tension force is included.
  
  In the theory of the VOF model, the surface tension force is added to the momentum equation as a source term. However, in the Eulerian model, we have two momentum equations, one for the liquid and one for the gas.
  
  How is the surface tension force included? is it added to the liquid momentum equation?is it added to the gas momentum equation? is it split between the two phases? If it is split, is it split by two volume averaged factors or two mass averaged factors?
  
  Unfortunately, the theory manual does not mention related information under the Eulerian model theory.
- September 4, 2018 at 1:10 pm
  
  DrAmine
  Ansys Employee
  
  Give me some more time for reflection and I will get back to you!
- September 4, 2018 at 2:26 pm
  
  mohamedh
  Subscriber
  
  Thanks for your interest. I would be very thankful for you if you could help me.
- September 4, 2018 at 2:55 pm
  
  DrAmine
  Ansys Employee
  
  It is just multiplied with the volume fraction of the phase and applied for each momentum equation set of each phase. So if you add both momentum equations set for two phase flows you will end up with the source term applied for the bulk (like in VOF method). Please bear in mind that as ANSYS Stuff I cannot provide more information about the implementation on this open community.
- September 4, 2018 at 3:07 pm
  
  mohamedh
  Subscriber
  
  Thank you so much. That answers my question. That means it is split by two volume averaged factors.
  
  I appreciate your help a lot. Thanks
- October 7, 2023 at 5:04 pm
  
  Mohammed OUALLAL
  Subscriber
  
  You can not find anywhere the surface tensioin in Navier-Stockes equations. In terms of forces, you have body forces and volumetric forces (they are balanced with the acceleration in N-S). Surface tension is related to linear forces, which is related to boundary conditions.
  If you wanted to include surface tension for instance for a bubble ascending in a water pool, just use Young-Laplace equation to get your surface tension.
- October 9, 2023 at 10:44 am
  
  Rob
  Forum Moderator
  
  You will find surface tension in the multiphase models, these add terms into the core solver equations which are based on NS equations.