Mesh Adaption in Ansys Fluent - Part 2: Geometry-Based Adaption

Mesh Adaption in Ansys Fluent - Part 2: Geometry-Based Adaption Hello everyone, this is Mohsen Seraj. I'm a senior and system application engineer working in Ozen Engineering. Today, I'll be continuing our discussion on geometry-based mesh adaption in Ansys Fluent.

In this part, I'll show you how to set up this geometry mesh adaption, building upon the previous mesh adaption we had for the boundary layer and pressure gradient. Before we dive into geometry-based mesh adaption, let's review what we found from Part 1 regarding the initial mesh.

For the best mesh adaption, we need to set up the geometry-based practices for formation options in the initial mesh. The initial mesh should not be too coarse, as it may not accurately represent the geometrical features, such as curved boundaries or sharp corners.

Additionally, the initial mesh should have sufficient cells to capture the physics of the problem and the main characteristics of the flow field. In the first part, I covered the solution path, including mesh adaptions, comparisons with manual mesh adaptions, and comparisons with manual ira.

Now, let's move on to the trial mesh. Unfortunately, creating meshes for complex assemblies, such as the finned metal key pattern, can be a significant challenge.

To address this, we can create an envelope on the locations or the whole domain where we want to have the mesh adaptation based on the geometry. We will use a surface mesh, created from the volume mesh, for the auxiliary geometry.

The volume mesh will be used to perform the mesh adaptions for the boundary layer, pressure gradient, and geometry-based mesh adaption. Before starting, ensure that the units for creating the surface mesh match those used for creating the volume mesh.

For the surface mesh, use a local mesh that is much more refined than the volume mesh. For curved boundaries, increase the segmentation from six to nine or ten partitions.

Ensure that the surface mesh can handle sharp corners and has a good resolution to capture the curvature and what's happening for the geometry. Now, let's prepare the geometry for the self and save the surface mesh in the legacy mesh file format (.gz) to ensure compatibility with Fluent.

Next, we'll move on to the volume mesh for the domain. After checking the mesh quality, we have a minimum orthogonality of 0.27, which is good. The number of cells is 5900, close to our previous value of 2700- 2800. Now, let's visualize the mesh.

Moving on to the setup for the mesh adaption, we'll start with the solid filament. Define AUX19 and AUX20 for the walls and corners. Use these auxiliary geometries for the wall zones and faces. Next, define the boundary layers for the refinement character.

Use two cell sets, one for the boundaries and another for the pressure gradient. We'll use these sets for the mesh adaption. Now, let's create a new mesh adaption based on pressure gradient. Set the maximum cell count to 500,000 and use the predefined criteria for pressure gradient.

With the setup complete, let's check the mesh quality. The minimum orthogonality is 0.27, which is above 0.15, indicating acceptable mesh quality. The number of cells is 2576. Visualize the mesh, and you'll see one to three cells for the curved boundaries, inlet, and outlet.

Additionally, you'll see three cells for the sharp corner. Now, let's create a plane similar to the previous one. You can see the mesh quality on this plane. During the solution, you can monitor the cell numbers and see how the mesh adaption occurs in the domain.

After the solution, you'll see the destroyed cells at each jump, indicating the mesh adaption in the domain. Finally, let's look at the geometry-based mesh adaption option, which creates a curved boundary between the initial nodes.

This option provides a much better representation of the actual geometry. Thank you for watching. In the next video, I'll show you how to build up and set up the geometry-based mesh adaption using auxiliary geometry.

You'll learn how to add nodes between initial nodes, reconstruct the geometry, and match the original geometry. This will give you a much better resolution for the geometry. Remember, when working with complex geometries, manual refinement can be time-consuming and may not result in a good mesh.

Using geometry-based mesh adaption can help match the resulted mesh with the original geometry shapes and improve the mesh in critical regions. Thank you for watching, and don't forget to check out Part 1 of this video series.