[Crank-Shaft]

Fellow CFD-enthusiasts,

I have been looking for a way to modify the boundary conditions and increase the number of blocks in the CGNS grid files located here -
https://turbmodels.larc.nasa.gov/naca4412sep_grids.html

I am interested in these files -

• (3-D) 2 x 1793 x 513 (2 x 1025 points on airfoil surface) (13.2 MB)
• (3-D) 2 x 897 x 257 (2 x 513 points on airfoil surface) (3.4 MB)

I have a research CFD code and want to modify the boundary conditions given (as they are not implemented) and also increase the number of blocks by equally splitting at selected grid points to export a multiblock CGNS grid with lots of equally balanced/weighted blocks for efficient parallelisation.

Does software with a top down approach achieve this (Pointwise, GridPro)?
Is this possible on ICEM?

Are there utilities to directly modify CGNS grids? So far I've only seen interpolation and format translation tools in the official site.

Any help or suggestions are greatly appreciated.

Best wishes,

[vimaero]

Hi,

If you are able to convert the cgns file to FLUENT/hex/plot3D format, you can then convert that grid to topology in GridPro and then do the required modifications on the topology to generate the desired grid. But increasing the no. of blocks at the grid level is not possible in GridPro.

Best Regards,
Vimal

[Crank-Shaft]

Thanks for your response. Unfortunately, I do not have GridPro access at the moment and I've been trying to register for the free academic trial licence. I've entered my details but haven't heard a response yet from the website.

Meanwhile, I'd like to ask for assistance with my ICEM file. I am not sure whether there are issues with the large domain size and the profile of the aerofoil being 100x smaller, but there are small errors near the edges of the NACA profile and the edges and curves just don't seem to match.
This creates a layer of near-wall cells and the pre-mesh checks have a lot of negative Discriminants. I've tried to redo this several times and re-created the aerofoil curves in different ways but this is persistent. I am wondering if there's a resolution or edge/curve tolerance issue.

If someone could look at the .tin and .blk files attached and share some ideas, that would be greatly appreciated!

Kind regards,