[swm]

Hi guys,

I've encountered a strange problem which keeps puzzling me for a week
I exported a mesh with CGNS format in Numeca Autogrid and then imported it with Pointwise, but it failed!

The error message is clear: 'File contains multiple base nodes'. I also looked it up in the User manual which told me pointwise could only load CGNS mesh with single base node.

I'm wondering when I export CGNS mesh in Autogrid, whether I set something correct or just need to modify some parameters to make pointwise can load the kind of CGNS mesh.

Does anybody have any suggestion or solution? (Although I can export the mesh in Autogrid with Plot3D format, it loses all the BC info which is critical to show the connection between multiple blocks. So that I have to export it with CGNS format)

Many thanks.

[DarylMusashi]

Dear swm,

indeed AutoGrid5 CGNS files contain several bases. I found the following passages in the IGG manual:

"A CGNS base contains the information on the mesh blocks, their connectivity and boundary conditions. IGG™/AutoGrid5™ can write several bases, they are described hereafter according to their name. The first one is mandatory for a computation, the other ones are optional and not always present.

Base#1
This base is the main one and contains the useful information about the mesh to be run by the solver.

Butterfly_base
This base contains mesh information for the parent block of a butterfly topology. Internal use only.

meridional_base
For a turbomachinery mesh, contains a meridional mesh that will be used by FINE™/Turbo for the computation initial solution. Internal use only.

tools_base
This base contains information for post processing and some other information for AutoGrid. Internal use only."


You could give it a try and manipulate the AutoGrid5 CGNS file with ADFViewer. Its part of CGNSTools, which can be downloaded here, for example: https://sourceforge.net/projects/cgns/files/cgnstools/, Release 2 contains a windows version.

After installation you can read in CGNS files. In the attached screenshot you can see the different bases from a typical AutoGrid5 file. With right-clicking you can delete the meridional and tools base, for example. The turbulent data bases in my example only exist if FINE/Turbo did calculations on this mesh, so they shouldn't be there in your case.

After deleting all unnecessary bases except "Base#1" maybe Pointwise is able to read the mesh now. May I ask why and how you want to further modify the mesh in Pointwise?

[swm]

Hi Holger,

Thank you for your suggestion. The software you recommend is downloaded easily but the SETUP.exe can not work in my laptop (WINDOWS10).

Actually I won't use Eurans to run CFD cases but just use Autogrid to generate grid as fast as possible. A set of in-house CFD code developed by ourselves will be used to solve CFD problems. But it can only accept plot 3D grid and BC conditions written in Gridgen Generic format. So that I have to convert the format by Gridgen or Pointwise.

This finite volume solver can only handle structured multiblocks. If I want to increase the computational efficiency with MPI, I have to split some blocks to make each core have equal nodes approximately. Moreover, the mesh generated by Autogrid automatically can not meet the requirement of DES/LES computation in some cases, you'd better improve the mesh quality in some critical region by more powerful mesh generator, such as Pointwise.

Thanks for your help.

swm

[swm]

Hi Holger,

Thank you for your suggestion. The software you recommend is downloaded easily but the SETUP.exe can not work in my laptop (WINDOWS10).

Actually I won't use Eurans to run CFD cases but just use Autogrid to generate grid as fast as possible. A set of in-house CFD code developed by ourselves will be used to solve CFD problems. But it can only accept plot 3D grid and BC conditions written in Gridgen Generic format. So that I have to convert the format by Gridgen or Pointwise.

This finite volume solver can only handle structured multiblocks. If I want to increase the computational efficiency with MPI, I have to split some blocks to make each core have equal nodes approximately. Moreover, the mesh generated by Autogrid automatically can not meet the requirement of DES/LES computation in some cases, you'd better improve the mesh quality in some critical region by more powerful mesh generator, such as Pointwise.

Thanks for your help.

swm

[swm]

Hi Holger,

Thank you for your suggestion. The software you recommend is downloaded easily but the SETUP.exe can not work in my laptop (WINDOWS10).

Actually I won't use Eurans to run CFD cases but just use Autogrid to generate grid as fast as possible. A set of in-house CFD code developed by ourselves will be used to solve CFD problems. But it can only accept plot 3D grid and BC conditions written in Gridgen Generic format. So that I have to convert the format by Gridgen or Pointwise.

This finite volume solver can only handle structured multiblocks. If I want to increase the computational efficiency with MPI, I have to split some blocks to make each core have equal nodes approximately. Moreover, the mesh generated by Autogrid automatically can not meet the requirement of DES/LES computation in some cases, you'd better improve the mesh quality in some critical region by more powerful mesh generator, such as Pointwise.

Thanks you for your help.

swm

[DarylMusashi]

Dear swm,

thank you for your detailed answer. To be more precise I downloaded the installation package "win 2-5-2" yesterday: https://sourceforge.net/projects/cgn...20Release%202/. This worked properly for me and I use Windows 10, too. Maybe you want to check your security settings or share the error during installation?

Secondly, I understand your problem with splitting the blocks equally for MPI parallel computations. You could do this easily in IGG with the "split block" function in the top left control bar after you have generated your mesh in AutoGrid.

May I ask which mesh regions or quality criteria are not satisfying for you? You say Pointwise is more powerful than AutoGrid. Does it have additional features for mesh creation or is it only more user friendly and gives you more control over the parameters? I strongly suppose the latter.

Finally, maybe its interesting for you to know, that FINE/Turbo is capable of DES computations. ("The DES (Detached Eddy Simulations) model has been implemented in FINE™/Turbo. For more information, please contact your local support office."). Secondly, FINE/Turbo solver is able to use a "parallel partioned" technique, so it splits the blocks automatically for perfect load balancing.

Kind regards
Holger