Dynamic Mesh UDF for 3D case using DEFINE_GRID

Dynamic Mesh UDF for 3D case using DEFINE_GRID_MOTION

- December 13, 2022 at 7:59 pm
  
  bv169
  Subscriber
  
  Hello,
  I am writing a UDF for dynamic mesh on a face of a domain using DEFINE_GRID_MOTION. The goal is to be able to put in x,y,z coordinates to update each time step that moves the nodes in the z direction (up and down). I have a UDF drafted but when I preview mesh motion it does not change the mesh. The base UDF I used and edited for my use was for a 2D simulation. I thought maybe that it did not work because I am using z coords so I added the #ifdef RP_3D statement before the references to z coords, but it still is not working. The udf compiles and loads without error, but nothing happens when I set preview mesh motion. Is there something else I may be missing here? I have the x,y,z coords as vectors to update each time step and the SET_DEFORMING_THREAD_FLAG to check that nodes need to be updated. Additionally, if there is a simpler way to achieve the goal I am aiming for please let me know! I tried using a profile but don't see a good way to do it this way based on examples I have seen.
  Thanks,
  Breanna
- December 14, 2022 at 11:58 am
  
  Rob
  Ansys Employee
  
  Are you trying to deform something or move a rigid body? More information will help. Otherwise, check whatever triggers the motion is triggered and that the UDF is correctly hooked in: the latter is covered in the documentation.
- December 14, 2022 at 3:17 pm
  
  bv169
  Subscriber
  
  So I have a flat face on the top of a domain and I am trying to move certain coordinates of the mesh on that face up or down to another certain z coordinate according to a dataset I have. From the tutorials I completed this seems to required the DEFINE_GRID_MOTION UDF.
- December 14, 2022 at 3:34 pm
  
  Rob
  Ansys Employee
  
  That looks OK. You may need to add in some terms so the solver can find the nearest node to your data set. If you set a precise position and there isn't a node nothing will happen.
- December 14, 2022 at 3:40 pm
  
  bv169
  Subscriber
  
  Okay I am guessing that's the issue! Is there a specific place in the customization manual I can find these terms to add? Thanks!
- December 14, 2022 at 3:42 pm
  
  Rob
  Ansys Employee
  
  Possibly here? https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v222/en/flu_udf/flu_udf_DataAccessMacros.html%23flu_udf_GridNodeMacros

Viewing 5 reply threads

You must be logged in to reply to this topic.

Ansys Innovation Space

Earth Rescue – An Ansys Online Series

The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.

Ansys Blog

Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.

Trending discussions