AutoMesh - Recent Threads

Mastering Turbine Mark-II Meshing – A Step-by-Step Automation Guide Using Fidelity Python API

Gaurav — Mon, 19 May 2025 02:06:28 GMT

In this case study, we will be examining the meshing workflow process for a turbine nozzle guide vane, specifically the Mark II model. The primary objective is to demonstrate the capabilities of the Fidelity Python API script in accurately generating a mesh for a 2D high-pressure turbine blade. Through this example, we intend to illustrate how the API can efficiently manage complex meshing tasks, providing users with valuable insights into various key meshing parameters.

https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1OPP000000sTWU2A2&pageName=ArticleContent

Export .geomTurbo to .IGS

Hans Hager — Thu, 19 Dec 2024 11:20:11 GMT

Dear Numeca-Community,

I lost my original CAD for a comrpessor blade. Right now I have only the .geomTurbo File for grid generation.
Is it possibly to export back into a neutral CAD format like *.iges

Best regards,

Hans

Option to group surfaces not available in the Geometry context

Colinda — Mon, 05 Aug 2024 13:41:26 GMT

I have a .step file and made a mesh on it.
Then I realized that several surfaces needed a refinement. So I wanted to group these.

I go back in the Geometry context and select the surfaces (all under the same boundary) and right-click.
To my surprise the option to group them does not appear.

When I open the same step file in a new project from scratch and try to group these same surfaces, it works. So I guess there must have been something in the process of setting up the domain and mesh that caused the grouping to no longer be available. But I can’t figure out why.

Structured Vs. Unstructured Mesh

CFDTech — Tue, 26 Sep 2023 07:06:09 GMT

Appropriate mesh generation is essential for an accurate solution, faster convergence, and reduction of numerical diffusion. Poorly formed meshes introduce numerical error, increasing the computational cost of convergence. For especially poor elements, the numerical order may be locally reduced to promote convergence and stability or, even worse, the solution may fail to converge entirely.

Structured	Unstructured
1. Structured grids are identified by regular connectivity (ordered type by indices such as i, j, and k and the topology is easily associated to the next indices). The possible element choices are quadrilateral in 2D and hexahedra in 3D. The regularity of the connectivity lets you conserve space because neighborhood relationships are defined by the storage arrangement.	1. Unstructured grids have no such ordering. Therefore, a node is associated to a single integer index and the topology is known by associating connections of the node with the neighboring nodes. Compared to structured meshes, the storage requirements for an unstructured mesh can be substantially larger because the neighborhood connectivity must be explicitly stored.
2. Grids can be Cartesian or Curvilinear (usually body-fitted). In the Cartesian grid, grid lines are always parallel to the coordinate axes. In the Curvilinear grid, coordinate surfaces are curved to fit boundaries. There is an alternative division into orthogonal and non-orthogonal grids. In orthogonal grids (for example, Cartesian or polar meshes), all grid lines cross at 90º. Some flows can be treated as axisymmetric, and in these cases, the flow equations can be expressed in terms of polar coordinates (r, θ), rather than Cartesian coordinates (x, y), with slight modifications.	2. Grids can be triangular (tetrahedral), quadrilateral (hexahedral), polygon (polyhedral), and hybrid. Unstructured grids can accommodate completely arbitrary geometries. Grid generators for such meshes are also very complex.
3. Advantages of structured girds are better convergence, a high degree of quality and control, less memory and time resolution (does not need the storage of any connectivity table because the mesh is defined according to a specified pattern).	3. Advantages of unstructured grids are the ability to handle complex geometries and the possibility to generate anisotropic meshes in the far field without cell clustering and propagation, ideal for marine applications, for example, to capture the free surface and keep the lower cell count.
4. Structured meshes can be generated using a variety of well-defined mathematical techniques, ranging from algebraic to conformal mapping to the solution of partial differential equations.	4. Algorithms used to generate unstructured meshes are generally based on the Delaunay algorithm or an advancing front technique.

Unstructured meshes are generated using Fidelity Hexpress and Fidelity Pointwise.

Two different generation approaches are available in Fidelity Hexpress and can serve different purposes based on the inputs and needs of the user:

Volume-to-surface approach: Generation of the mesh starts from the domain volume, and it is successively adapted to the geometry. This approach is particularly convenient for complex geometries and unclean geometry inputs (for example, non-watertight geometries, non-conformal triangulations).

Surface-to-volume approach: Generation of the mesh starts from surfaces of the geometry and is successively propagated to the domain volume. This approach can produce very high-quality unstructured meshes with very tidy cell patterns on the surfaces. It requires conformal geometries.

Fidelity Autogrid technology automates the laborious geometry preparation process without losing any detail of the geometry and delivers quality meshes ready for CFD simulations in real real-time and is used for turbo machinery configuration.

Figure 1: Unstructured mesh generation done by Fidelity Hexpress

Figure 2: Structured mesh generation done by Fidelity Autogrid

Fidelity Pointwise can generate structured multi-block, unstructured, hybrid, and overset meshes for viscous simulations with precise control over point placement and clustering to get the desired resolution. At the same time, Pointwise’s core meshing methods produce cells of high quality to ensure convergence and accuracy in your CFD solution.

Figure 3: Unstructured mesh generation done by Fidelity Pointwise

Team CFDTech

Cadence Design Systems

3D mesh generation failed. Could not create fillet geometry. No blend surfaces created.

Hans Hager — Wed, 03 May 2023 15:12:58 GMT

Hi,

so I want to mesh one passage of a turbine stator with hub and shroud fillet. I used a mesh that I work with and uploaded the Aachen Stator2 into it by "Import and Link CAD" (importing .geomTurbo and then using link to Blade/link to trailing edge/link to leading edge).

When I try to mesh it, the following error occurse.

What might be wrong?

Regards,

Hans

3D mesh generation failed. Could not create fillet geometry. No blend surfaces created.

Hans Hager — Mon, 24 Apr 2023 08:20:15 GMT

Hi,

I am trying to mesh a full annulus in AutoGrid5 by taking the mesh of one passage and then duplicating it to get a full meshed turbine stator annulus. Now the Fillet mesh works for one passage (O4H topology with Butterfly fillet geometry; Method:from meridional; structured mesh; highly staggered; matching periodicity).

Unfortunately I get the following error message:

Somewhere along the way on the annulus, the fillets cannot be generated anymore.

What could the reason be?

Regards,

Hans

3D mesh generation failed. Could not create fillet geometry. Cannot create valid fillet lofted surfaces.

Hans Hager — Mon, 24 Apr 2023 07:26:44 GMT

Hi,

I am using AutoGrid5 and I tried to mesh a turbine Blade (structured mesh, highly staggered, O4H) with Butterfly fillet topology (Method: B2B section offset).

Unfortunately I get the following error message:

What could be the reason?

Regards,
Hans

Export to .msh fluent format

Teja971201 — Tue, 28 Feb 2023 14:06:55 GMT

Hello,

I recently acquired a student license for Omnis and am working on only rotor simulations. I have generated the mesh and when I export it, I cannot see the fluent .msh file format. Could someone help me with that? I used that option in the old version of Autogrid with IGG. But is there an option like that in the new OMNIS5.2?

Thanks.

M_Mesh Setup 1 Error 255: ssh error

aescudero — Mon, 30 Jan 2023 11:59:30 GMT

Dear all,

I have a student license and I am trying to reproduce the volute tutorial. I follow the steps which are indicated but when I arrive to the end and I run the mesh, I receive the next error message: 'M_Mesh Setup 1 Error 255: ssh error'

Can anyone please explain which is the source of the error and/or how to fix it?

Thank you very much,

Alvaro

Create a Conformal Mesh?

Lefort — Thu, 21 Jul 2022 16:11:36 GMT

Hello,

I have been trying to use Hexpress 11.1 to create very coarse unstructured meshes. (less than 1000 cells for a 3D wing) I have been running into a few issues

Vertex matching at cell edges is required by our flow solver. Vertices such as those shown in the image are problematic. I was wondering if there was a way to prevent the mesh generator from producing these features. (generating a conformal grid)

IGG connecting multiple blocks to a common interface for Volute meshing

JosephSmith — Sat, 04 Jun 2022 18:30:18 GMT

Hi everyone! I am a beginner attempting to mesh a volute in IGG. The cad is seen in image 1. I have also split the CADs surfaces further to attempt to make the blocking process easier

Image 2 below shows an upclose region near the cutwater. At this section, it seemed appropriate to split the mesh into two parts: A and B, extrude them separately and then set full non matching boundary conditions on the patch where they have a common interface.

I tried to extrude the portion of the face B seen below in image 3.

The portion A of the face was then extruded separately in image 4:

The two extrusions next to each other are in image 5:

The last image is my attempt at first trying to split the circular extruded section A into a patch near the common interface of B. Then setting the two patches between A & B's extrusion to full non matching.

I would like to know if the above process may be incorrect, or if there is a more suitable way of approaching this problem.
I have tried to use methods from the IGG tut 3&4 to tackle the problem but would appreciate a second opinion.

Seed point is too close to one of the geometry boundaries.

Colinda — Tue, 22 Mar 2022 14:30:31 GMT

When I generate a mesh, a warning appears that indicates that the seed point is too close to one of the geometry boundaries. Is this expected? It looks like the mesh is good.