Fluids

Fluids

User Defined Function Help

    • h_pigg
      Subscriber

      I am trying to simulate an oscillating wave energy converter in Fluent. I would like to use a dynamic mesh so that the flap of the device can rotate back and forth with a fixed bottom point in response to waves that interact with it. I am brand new to dynamic meshing and user defined functions so I am not totally sure how they work. I have attached an image of my current geometry. The water level will be near the top of the rectangle and I would like the bottom to be able to be fixed. A damping element for the rotation of the device would also be useful.

      Thank you so much in advance!

    • YasserSelima
      Subscriber
      You need to use SDOF properties ... You have single degree of freedom movement which makes the problem slightly easier. But, you need to provide center of rotation and the properties of your mass, Inertia, CG .... Damping could be added as an external force. nAs this is your first UDF, go read the Dynamic mesh in the UDF manual and look at the examples in SDOF. It takes sometime, only the first time!nGood Luck!n
    • Keyur Kanade
      Ansys Employee
    • sugarl14
      Subscriber
      have you made any progress on this? I am trying to do the same thing and I am also brand new to dynamic meshing in Fluent.nnAlso, instead of using a UDF for this oscillating wave surge converter example, couldn't you just create a SixDOF Property? (e.g. Dynamic Mesh -> Six DOF -> Settings -> Create/Edit)nnthanks!nLando
    • h_pigg
      Subscriber
      I haven't been able to make too much progress but as you mentioned, I realized I did not need the UDF yet. I have been trying to get results with the smoothing and remeshing options enabled. For smoothing, I chose the diffusion based method because the spring based method was creating negative cell volume errors (at least I believe it was). Now the error I am having is that my WEC is shrinking in size for reasons that I can't pinpoint. n
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