Fluids

Fluids

Flapping Mechanism in ANSYS Fluent (UDF)

    • Vishal Ganore
      Ansys Employee

      Hi Friends,


      Modeling flapping mechanism in Fluent needs considerable effort and time since you are bringing flapping motion (needs motion UDF, good quality mesh, additional dynamic mesh setting, turbulence etc.). Many students are trying to solve such problems. So I am sharing following useful materials/information to get you started:


      1. Generate good quality mesh around flapping region 


      2. Refer this flapping door tutorial (files are attached):


      Part 1 Problem setup and results: 



       


      Part 2 (UDF and Dynamic mesh):



       


      3. Flapping tube tutorial discussion: http://studentcommunity.ansys.com/thread/dynamic-meshing-of-bending-tube/?postbadges=true


       


      4. Here is my blog on similar flapping wing: http://www.ansys-blog.com/dragonfly-flapping-ansys/


    • wbmckinney
      Subscriber

      What version of Microsoft Visual Studio would you recommend installing to compile the UDF? I was trying to install VS Express 2012 but cannot find it available anywhere. Please let me know your thoughts.


      Thanks,


      Will McKinney

    • Vishal Ganore
      Ansys Employee

      This information is available in ANSYS Fluent manual for respective ANSYS versions. 


      2012 VS Express + VS SDK is available here: https://www.visualstudio.com/vs/older-downloads/


      If you are using latest ANSYS products 18.0 and above, you could go ahead with latest 2017 VS Community. 

    • ankushcool288
      Subscriber

      I followed your tutorial step by step but some error is popping up and I quote "the udf library you are trying to load is not compiled for 2ddp on the current platform(win64)".


      Please explain to me how can I remove this error.


       

    • Vishal Ganore
      Ansys Employee

      May I know how are you launching Fluent?? Are you using VS compiler and MS SDK? If possible, please share your project file achieve (.wbpz).

    • ankushcool288
      Subscriber

      I am happy to tell you that I have removed my errors with the help of my friend. Your tutorial helps me a lot and I want to explore more about it. Please keep sharing.


      Thank you

    • wbmckinney
      Subscriber

      I am having issues with my model for the flapping tube. Vishal, you recommended to not have a thickness on the tube. However, I am having trouble inputting the tip region of the tube as a wall BC instead of an interface BC. Right now I have 2 separate parts in my model: the atmosphere and the tube. Also, I get an error when I try to run the dynamic mesh saying negative cell volume. Please let me know if you have any suggestions.


      Regards,


      Will McKinney

    • Raef.Kobeissi
      Subscriber

      Nice tutorial!

    • jaiswal.3
      Subscriber

      Hi Ankush


      I am also facing the same problem you have faced.Can you help me to remove this error out? Any help from your side will be really helpful

    • jaiswal.3
      Subscriber

      Hi Vishal,


      Nice Tutorial.I am also working in the area of hydrodynamics of oscillations.Please guide me, how to start with UDFs and what are the prerequisites,like software compatibility and what are the necessary steps before compiling the UDFs.I have tried your tutorial and facing the error like "The UDF library you are trying to load is not compiled for 2D on the current platform.The system cannot find the file specified." 


      Please Help


      Thanks


      Manish 

    • Vishal Ganore
      Ansys Employee

      Manish, Can you provide following details?


      1. Which Microsoft compiler are you using?


      2. Which version of ANSYS?


      3. How are you launching Fluent? Through workbench or standalone mode or through MS SDK command prompt?


      Files (including UDF and fluent case) are attached above which you can take and test. My understanding is you have a compiler issue. 


       


       

    • jaiswal.3
      Subscriber

      Thanks Vishal,


      The microsoft compiler which I am using is Visual studio 2010


      I am using ANSYS '13'


      I am launching Fluent through Workbench,


      I also think that there is a compiler issue, how to fix that.

    • mahdishuvo
      Subscriber

       Vishal,


      Thanks for the tutorial. I have followed the similar equations and UDF but the motion of the body is not harmonic. the body is rotating around the center of rotation. What could be the possible reason? I can share .wbpz file if you want.


      Thanks.

    • mahdishuvo
      Subscriber

      My default time step was 1. If i make the time step to 0.1, it oscillates nicely. I don't actually get why this happens. Can any of you give me some ideas?

    • DrAmine
      Ansys Employee

      Pretty tutorials


       

    • Karthik R
      Administrator

      Vishal,


      This is an excellent tutorial. 


      Thanks.


      Best Regards,


      Karthik

    • psalmsyst
      Subscriber
      Thanks for this tutorial.
      However, I will like to know what part of the code Is responsible for the fixed end. What if I want the right end to be fixed while the other end flaps?
      I have a similar project but my door is vertical. Will like to know how to make either ends fixed
    • Vishal Ganore
      Ansys Employee

      Define the center of gravity location that we specify in Dynamic mesh zone in Fluent panel. The code only defines the motion of the rigid body. 

    • Philipmorris
      Subscriber

       


      Excuse me, May i ask you about the udf. I 'm simulate 2D unsteady pitching of rectangular plate. The motion of the rectangular plate in cross-flow y direction is expressed by



      My question , Can i used your UDF but change COS to SIN.


      Thanks for your kindness

    • Shuvadeep
      Subscriber

       @vganore


      In the tutorial above, where is the origin. Is it at the plate center or at the hinged point?

    • sarvapriyasingh
      Subscriber

      could you please help me out in the same error what you were getting ?

    • rexfoxoloughlin
      Subscriber
      I'm getting the same errors, did you figure it out?n
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