fluent meshing mode

Hello,

I'm using fluent meshing mode to create mesh. When I create surface mesh, I get the error message:

error: arg(3rd) out of range in substring

error object: 6

Can anyone help me to find the possible reason?

 

Thank you,

«1

Comments

  • RobRob UKForum Coordinator
    edited November 2019

    Pictures and setting will help. Remember to post images in with the text as staff are not permitted to open/download attachments. 

  • GenfGenf Member
    edited November 2019

    watertight geometry workflow is used 

     

    Thank you,

  • RobRob UKForum Coordinator
    edited November 2019

    I wonder if it's the Student version hitting the cell cap.  Increase the smaller cell size by a fair bit and see if it'll work. Then try and refine. You're capped at 512k cells, so if you have that many vertices I suspect you're creating too big a mesh. 

  • GenfGenf Member
    edited November 2019

    hi,

    I increased the minimum cell size to 5, it still has this message. I'm using academic license.

    I used these settings to generate mesh on my old computer using ANSYS 2019 R2, it worked.

    But after I transfer the model to a new computer and use the same settings, the error message came up. The ansys version on the new computer is 2019R3.

    thank you

     

  • RobRob UKForum Coordinator
    edited November 2019

    Meshing didn't change that much. Were you using Student on the old computer? Given the number of surface facets I don't see how it could work on Student. 

  • GenfGenf Member
    edited November 2019

    I'm using academic license on both computers. the problem may be caused by different versions of ansys. I have tried other fluent mesh files. Sometimes when I just open the mesh file and click on create surface mesh, the error message shows up:

    Error: arg(3rd) out of range in substring

    Error Object: 6

    Error: Illegal Variant cast from bool to class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >, data: False

    Error Object: ()

     

    thank you

  • RobRob UKForum Coordinator
    edited November 2019

    Teaching or research?  Also, what's the new computer & folder (full path) called?

  • GenfGenf Member
    edited November 2019

    Research, 

    computer name: Untaroiu-2

    fluent : C:\Program Files\ANSYS Inc\v195\fluent\ntbin\win64

      

     

  • RobRob UKForum Coordinator
    edited November 2019

    Not sure then: can you mesh a simple cube? 

  • GenfGenf Member
    edited November 2019

    yes, it works with a simple cube.

  • RobRob UKForum Coordinator
    edited November 2019

    So it's model dependent. Pick a big cell size (ie far larger than will resolve the flow features) and try again. I don't care about mesh quality, I want to see what the cell count is. 

  • GenfGenf Member
    edited November 2019

    Hi, I tried different settings for a simple cube. It also has errors some time. It seems like when a local size is added, the error message comes up.

  • RobRob UKForum Coordinator
    edited November 2019

    What's the local sizing set to? Also how big is the box?

  • GenfGenf Member
    edited November 2019

     The box is 21x21x30 mm, Local sizing: 5,

      

  • RobRob UKForum Coordinator
    edited November 2019

    Weird. That should give you about 4-6 cells on each edge. I assume the guide "cubes" are a sensible size?

  • GenfGenf Member
    edited November 2019

    Hi, what are guide cubes ?

  • RobRob UKForum Coordinator
    edited November 2019

    The green cube (they're red on my display). They show the expected cell size, you'll typically see two sizes for a min & max. Can you turn off proximity: I wonder if you've created an impossible set of conditions for the mesh. Ie the surface mesh can't be true for both the local & surface sizing. 

  • GenfGenf Member
    edited November 2019

    The proximity is turned off, but still the same message. The error occurs when reading the temporary .sf file. When I remove the local sizing, it works with the same setting under 'create surface mesh'.

    If I make the local sizing on all the surfaces same as the minimum size under 'create surface mesh', What possible changes can local sizing add to the mesh? Is the local sizing information stored in .sf file ? Is it possible to view the details in .sf file ?

     

  • RobRob UKForum Coordinator
    edited November 2019

    The sizing on the surface will be a function of the size functions and local sizing. Given it's a cube curvature is unlikely to do much, so sizing will be set by proximity. You can probably get the size function out from the tree (not the workflow) but I'll leave that for you to find: I rarely use that feature. 

  • GenfGenf Member
    edited November 2019

    thank you for the explanation. The errors occurs when I transfer files to a different computer (same settings), so I doubt it might be caused by software installation.

    But do you have suggestions on how to set element size on a specific surface in fluent meshing mode ?

    I'm new to fluent meshing, Do you recommend to use workflow in fluent  for mesh generation ?

    Thank you

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