How to include particle drag force in momentum exchange source term

- June 28, 2021 at 8:16 pm
  
  sowmiya.krishnaraj
  Subscriber
  
  Hi all,
  I need to include momentum source term to bring out two phase simulation of particle-fluid interaction,
  I have included the drag coefficient in DPM_DRAG MACRO and calculated the drag force in fluent. Now I need to include that calculated drag force in momentum source term through UDF.
  I couldn't find any macros to include the drag force directly into the momentum source term.
  Please kindly give me some suggestions to carry out my simulation.
  Many thanks in advance
- June 28, 2021 at 10:29 pm
  
  ai0013
  Subscriber
  
  Is there any specific reason why you need to include drag force as momentum source via UDF? Why don't you just enable the two-way coupling
- June 30, 2021 at 7:49 am
  
  sowmiya.krishnaraj
  Subscriber
  
  Hi,
  Thanks for response.
  I tried two-way coupling I could find a tiny change in velocity contour but I need to find out whether the change is because of the inclusion of Rsl term (volumetric fluid -particle interaction force ). It would be better if I include this term via udf in cell zone condition. Please kindly give me some suggestions if possible.
  Many thanks
- June 30, 2021 at 10:37 am
  
  Rob
  Forum Moderator
  
  You'd need to set the source term to mimic the drag effect, that should be possible but may be fairly complicated as you need to work out where the particles are relative to the cells then calculate the drag etc. I'm with on this one, unless you can explain why you need to see the value.
- June 30, 2021 at 12:23 pm
  
  sowmiya.krishnaraj
  Subscriber
  
  Hi Rob Thanks for your valuable suggestions.
  I am calculating the drag force using cunningham drag force formulation where the particles Reynolds number are relatively less and I have to check in such a way to see how it get influenced in the fluid mimicking to see how the particle gets affected while entering the pulmonary airways.
  Is there any examples available ?
  It would be grateful if I get some suggestions and comments.
  Many thanks
- June 30, 2021 at 2:39 pm
  
  Rob
  Forum Moderator
  
  The only examples are those in the UDF manual, we don't have anything else we can share on here. I doubt there would be much else on the Customer Portal either: your supervisor may have access to that.
- June 30, 2021 at 3:16 pm
  
  sowmiya.krishnaraj
  Subscriber
  
  Hi Rob Thanks for the suggestions it helps me a lot.
  Many Thanks