Fluids

Fluids

Fluent 6DOF dynamic mesh and VOF simulation

    • Alexander
      Subscriber

      Hi,


      I am trying to simulate a water wheel turbine with a 6dof dynamic mesh. I will later include VOF as well to model the interface between water and surface.


      At the moment I am following this tutorial to familiarise with dynamic mesh definition: 



      However, when I try to define the dynamic mesh, I tick 6DOF, go to settings and 6DOF Properties and Create/Edit... button don't appear (minute 7:28 of the video).


      Any idea why this does not appear and how can I introduce those properties?


      Many thanks.


      Alex


       

    • DrAmine
      Ansys Employee

      Do you mean the button of providing SDOF properties? With which version are you working?

    • Alexander
      Subscriber

      Hi Amine, thanks for the prompt response.


      Yes, I think that that is what I mean, please check the attached pictures. The first one is what I have, the second one what appears in the tutorial and in other examples that I have checked online. It seems to be the same menu but with the 6DOF properties definition missing.


      I am using version 17.1 of ANSYS Fluent.


      Many thanks for you help.


      Best wishes,


      Alex



       


       

    • DrAmine
      Ansys Employee

      Alexander you need to use newer release to use it otherwise only UDF is possible. 

    • Alexander
      Subscriber

      The newest version that we have is v17, I don't think I will be able to use a newer one for the moment.


      I am happy to use a UDF but I am not familiar with it. Could you share an example for a similar application or refer me to a tutorial about 6DOF UDF writing? Ideally I would need the equivalent UDF for that tutorial that I posted and then I could modify it myself for my application.


      Thanks,


      Alex

    • DrAmine
      Ansys Employee

      Check DEFINE_SDOF_PROPERTIES in the UDF manual. Here you might find two examples.

    • Keyur Kanade
      Ansys Employee

      Yes, you need to use udf. Though very old, please check following video to get idea about udf to be used with 6dof. 


    • Raef.Kobeissi
      Subscriber

      Why don't you try the newest Academic version?

    • Zain
      Subscriber

      Why don't you try the newest Academic version?


       


      Hallo Mr kobeissi


       


      Thanks for your advised, but how i can get academic version?


      Please help i realy need for these solution


      Regards


       


      Zain


    • Zain
      Subscriber

      We have same problem sir and im trying fix with udf tutorial but i cant find out how it works. if you already get the answer please share


      i realy need this solution for my application


      thank to everyone here for help


       


      Regards

    • Alexander
      Subscriber

      Hi Raef,


      I downloaded the latest version of Ansys/Fluent and I managed to run the simulation now. I will also give it a go with the UDFs though, in case I need them in the future.


      Many thanks,


      Alex

    • vishwatejakasoju
      Subscriber

      Yes, you need to use udf. Though very old, please check following video to get idea about udf to be used with 6dof. 



       


      I came across the tutorial you shared on 6DOF with Ansys FLUENT. While trying to replicate the simulation, i came across multiple problem. Although i resolved some of them, still unable to figure out few of them. I am new to Ansys FLUENT and have been struggling to get the issues solved quickly.  Any help on this will be really appreciative.


      1) i am unable to create two fluid zones as they did around the square block with the inner fluid zone moving with the square box. My first question is did they do your mesh in ICEM CFD or fluent mesh? 
       
      2) I tried having a small box outside my square box and then had a bigger box around it. So in total i have two fluid zones as they did but i am unable to mesh them the way its shown in the video. Then i do two different meshes (both a triangular meshes with different element sizes) for two fluid zones and later created a mesh interface between the inner fluid zone and outer fluid zone in fluent setup. I had the inner fluid zone and the mesh interface move with the square box. Also, defined the outer fluid zone to be deforming. I see the mesh to deform but I am always ending up with the same errors while running the simulation- Negative volume detected, failed to detect face headedness.
       
       
      3) Just wanted to confirm-for newer version fluent (i am using Fluent 2019 R3) if we are just doing a free fall test, there is no need to define a UDF function separately in .c file right?. We can create a 6DOF object and then add the mass and moment of inertia inputs and use that as reference while creating dynamic mesh. is that correct? 
       
      Could you please help me with any documentation you have on meshing the way its shown in the video/ help me resolve the error. Any help regarding this will be really appreciative.
       
       
      Thank you.
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