Fluids

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FSI with 2D

    • IA1996
      Subscriber

      How can i do an FSI analysis using a 2D model ?

      I've tried to extrude the model to a 3D model and do a one element through thickness mesh , but any change in the thickness will lead to a change in the results .

      What can I do ?

      Thank you in advance

    • Rob
      Forum Moderator
      Why will it change the results?
    • IA1996
      Subscriber
      First Thank you for your response .
      The problem is the following :
      I have a 2D model , I want to do a FSI analsysi ( which can't be done in 2D in ansys ) so i extrude the geometry to a 1mm thickness and i have a done a one element through thickness mesh , and I have done the fsi analsys .
      After that , I want to check if method is good , so i have make an extrude about 10 mm , then when i have run the analysis the results of stress and deformation was changed .
      The stress in the wall caused by the fluid has different value when i changed the thickness .
      So the result have differ .
      If there is any other solution to do the 2d fsi ?

      Thank you .
    • IA1996
      Subscriber
      This is an example of what i have faced, these two simulation the first is with a 1 mm thickness and the second with 3 mm thickness. The Imported pressure differ between the two thickness , also the shear stress at walls in the Fluent results.
      you can see the difference in the Equiv Stress Results with varying the thickness.
      Thank you in Advance
    • Ananth Narayan
      Subscriber
      Did the side face in your model contain one element in both cases?. Means- you need to set element size to 3mm in the second case because this will not form some kind of similarity I believe. Try doing this and share your results.
    • IA1996
      Subscriber
      Hello , Thank you for your response.
      Yes I already did that ( the element in the thickness for the second case is 3mm ).
      I've shared the results in the thickness for the two cases . You can see the imported load how it's differ also.
    • Rob
      Forum Moderator
      Check the pressure in Fluent. Reporting max values can be misleading if it's a tiny area that's affected. The resolution isn't that high either so you also need to review convergence and mesh resolution in Fluent.
    • IA1996
      Subscriber
      Hello Thank you for your response.
      I've tried to make better mesh , the results remain changing when I've tried a new thickness ( 0.1mm - 1mm - 5mm ).
      The results in fluent concerning the static pressure and wall shear stress have changed with each thickness ,
      Do we have a ratio of what thickness should we choose when doing FSI 2d ( one element through thickness ????
    • Rob
      Forum Moderator
      Can you post some results? Without knowing what you're looking at it's impossible to give any guidance.
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