Adjusting Line Surface with Local Reference Frame

Karl
Karl Member Posts: 2 ✭✭
in Fluids

Hello Developer Forum,

This question was originally posted to the Fluent Community Forum, and Federico (an Ansys employee) suggested I ask it here:

Hello Fluent community,

I’m running a transient simulation of a wind‐turbine rotor in ANSYS Fluent, and I’d like to examine how the boundary layer develops at specific spanwise stations on the blades in relation to the mesh growth rate. In a static‐mesh case I would simply:

  1. Define two points on the blade surface.
  2. Create a line surface between them (Surface → Create → Line → Through Points).
  3. Plot the velocity (or y⁺, etc.) along that line.

The challenge:
Because my blades are rotating, a fixed set of (global) start/end points no longer corresponds to the same physical locations on the blade as it spins. I know that Fluent lets you define a local coordinate system (via Define → Reference Frames) and attach it to a rotating zone, and that you can create a point surface in that coordinate system by choosing “Reference Frame” plus local coordinates. However, when I go to Surface → Create → Line, I can’t find any way in the GUI to specify that reference frame for the line—it always creates the line in the global frame—or a way to construct a line using the point surfaces defined within the local coordinate system.

What I’d like to achieve:

  • Define my spanwise probe‐lines once, in a blade‐fixed coordinate system—ideally by selecting a point on the surface and projecting it a specified distance normal to the surface.
  • Have Fluent automatically carry those lines around with the mesh at each time step.
  • Avoid writing an external script to recompute the start/end points at every time step and reposition them manually.

Questions:
1. Has anyone discovered a way—either in the Fluent GUI or via the TUI—to create a rotating line surface defined in a local (rotating) coordinate system, so that it follows the spinning mesh?
2. If not, are there any clever workarounds (e.g., using iso‐surfaces or adapting point surfaces) that achieve the same result?

This is all to help determine where a coarser mesh is acceptable and where refinements are needed—any additional methods or suggestions would be greatly appreciated.

Thanks in advance for any advice or pointers!

Simulation details:

  • Fluent 2024 R2
  • Transient, sliding‐mesh rotor domain (constant Ω)
  • Unstructured mesh with prism layers on blades

Interested in velocity profiles at 25 %, 50 % and 75 % span

Tagged:

Answers

  • James Derrick
    James Derrick Administrator, Employee Posts: 357
    Ancient Membership 100 Comments 100 Likes 25 Answers
    admin

    Hi @Karl this forum is specifically about coding and scripting using Ansys. If you have a more general Ansys question you would be better off heading over to the Ansys Learning Forum and asking there. https://innovationspace.ansys.com/forum/

    Otherwise, please could you provide any code you are having trouble with as well as details of what you've already tried and where you've already looked for answers.

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