Fluids

Fluids

Flow through a pipe – Problem in converting from Structural + CFX to Structural + Fluent

    • Alan
      Subscriber

      We went through the FSI tutorial from the ANSYS Portal about a flow through a plate. It is an external flow problem, while our problem of interest is an internal flow. Therefore, we plan to run a simple internal case.


      We first complete a Fluid-Structure interaction analysis in ANSYS using transient structural and CFX based on a tutorial on Youtube:

      The image shown below demonstrates the success 



      Then, we convert this case to a system coupling with Fluent, by using the exactly the same structural system, it failed pretty badly, please see the following images:



      Could you please help? 


      Thanks,


      Alan

    • Rob
      Ansys Employee

      As staff we can't download & check files, and we're limited in how much detail we can provide.


      Having said that, I'd look at the mechanical properties and time step sizes as it looks like the pipe section has collapsed. So it's possible moved too far in one step. 

    • Alan
      Subscriber

      We used the same mechanical property and time step for the System Coupling as for the Structural + CFX model. In general, should we reduce the time-step size once convert from CFX to System Coupling?

    • DrAmine
      Ansys Employee

      CFX and FLUENT are different codes. So settings which might fit CFX do not necessarily fit Fluent. The same applies for dynamic mesh settings (CFX default does only account for node smoothing). 


      Common error is that man applies a deforming zone for the interior-zone in Fluent. Here you need to do that for zone itself. Perhaps solution stabilization and URF for the load might be helpful. As rwoolhou already highlighted we're limited in how much detail we can provide so that I hope that other community members might chime in here.


       


      Good luck

    • Alan
      Subscriber

      Thank you, @rwoolhou and @abenhadj.

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