3-Way System Coupling (Thermal-Structural-Fluid)

- October 15, 2025 at 1:09 pm
  
  Isaiah
  Subscriber
  
  Hello everyone,
  
  Is it possible to do a 3-way coupling in ANSYS? So far, I've been able to get away with only doing 2-ways, as in, the fluid pressure deforms the structure, and the structural deformation affects the fluid flow/pressure generation. The time has now come where I'd like to include fluid flow, viscous heating, thermal expansion, and structural deformation from the pressure, basically all affecting the final result. I typically use system coupling in Workbench and went to tie in a third solver (Transient Thermal) and got the error "System coupling with more than two systems is currently not supported." I should also include that my structure moves and has structural boundary conditions, so only using the transient thermal module will not work (I believe). Are there any methods to accomplish my goals? Does anyone have some useful input? Using Ansys 2024R2 currently. Thank you for your time.
- October 16, 2025 at 1:47 am
  
  peteroznewman
  Subscriber
  
  Have you tried to use a Coupled Field Transient analysis instead of a separate Transient Thermal analysis and a Transient Structural analysis?
  That way there is only one Structural analysis to couple with Fluent.
  - October 16, 2025 at 12:12 pm
    
    Isaiah
    Subscriber
    
    Hello and thank you for your feedback,
    
    This is something I have not thought about as I do not typically use that solver. What I did do was manually change the elements in Transient structural to SOLID226 which did allow me to pass thermal data back into the structrual solver due to the additional thermal DOF, but as you can image this makes assigning further thermal BC's a bit more difficult since it would all have to be done using APDL commands. Today I will work on converting all the strutual items into coupled field transient solver as I do suspect this will allow me to move forward with ease. Thanks again for your valuable input.