The meshing module generates computational mesh for electromagnetic and thermal simulations. Simulation time and memory usage are primarily determined by it.

While automatic settings may work for preliminary simulations, further refinement is recommended for greater accuracy by applying specific conditions to volumes and faces. It’s advisable to start with a coarse mesh and gradually refine areas with high electromagnetic field gradients or regions of interest. Stop refining the mesh once the difference between refinements has reached the desired accuracy. This approach keeps the mesh coarse in less critical areas, ensuring an optimal overall mesh size and simulation time.

Settings

Adjusting the refinement conditions allows users to balance simulation accuracy and computational efficiency.

Mesh refinement – Global setting used to control the level of detail in the simulation mesh. Adjusting this option will refine the mesh across the entire domain, which can significantly increase mesh size and simulation time. It’s recommended to begin with a coarse mesh and then manually refine specific regions where higher accuracy is needed to balance detail and computational efficiency.

Meshing Algorithm – Netgen offers flexibility by allowing the addition of boundary layers on submeshes, making it more versatile. In contrast, GMSH is faster, more robust, and efficient for most tasks.

Min Size – This option is available only when using the Netgen algorithm. It sets the minimum element size, though other factors, such as submesh sizes or different algorithms, may override it.

Adaptive – This option is only available with the GMSH algorithm. The software checks the mesh quality after each iteration, adjusting parameters and rerunning meshing until the quality meets predefined criteria or the maximum number of iterations is reached.

Mesh settings tab for element size, growth ratio, and boundary mesh configuration

Meshing

Evaluate Mesh – The button is available before the mesh is created. This automatically calculates mesh parameters.

Compute Mesh  – Generates new mesh or updates the existing one based on the specified parameters and settings.

Dropdown menu:

• Evaluate – Reverts back automatically calculated mesh parameters.
• Preview in SALOME – Visualize and review the mesh using the SALOME pre-processing tool.

All Max Element Edge Size – Specifies the maximum size or length of the mesh element. This helps control the level of mesh refinement and ensures that the mesh elements are not too large.

Sub-mesh

Settings under this category assign mesh parameters to the selected geometrical part. Creating a sub-mesh allows users to individually control the meshing algorithms of specific sub-shapes, allow local variations in mesh density, and assign the order of meshing.

Meshing Algorithm – Netgen offers more options, making it more versatile. In contrast, GMSH is faster, more robust, and efficient for most tasks.

Min Size – Sets the minimum element size, though other factors, such as submesh sizes or different algorithms, may override it.

Growth Rate – This parameter specifies the allowable difference in linear dimensions between two adjacent elements. For example, a growth rate of 0.3 corresponds to a 30% difference in size.

Curvature Resolution – Specifies sizes for splitting curved edges and surfaces. The size is determined by dividing the local curvature radius by the curvature resolution value.

Submesh Priority Index – Submeshes are generated before the main mesh in the priority provided by the user. A higher value means higher priority.

Boundary Layers

It adds thin mesh elements on the surface of the sub-mesh to help resolve the skin layer while not significantly increasing the number of mesh elements. At higher frequencies, currents in conductors are pushed to the outer boundary; therefore, mesh refinement on surfaces mostly contributes to accuracy.

Total Boundary Layer Thickness – Sets the overall thickness of the boundary mesh layers. The software also pre-computes this value according to frequency and material properties. We recommend setting it to 1-1.5 times the skin depth.

Number of Boundary Layers – The number of boundary layers. Increasing this value allows for more detailed representation and improved accuracy in capturing variations within the boundary layer.

Stretch Factor – Defines the growth rate of the element thickness from the mesh boundary towards the interior. This parameter allows for fine-tuning the mesh resolution and capturing the varying properties and behavior of the domain closer to the boundary.

Setting mesh element size in the boundary mesh editor

Mesh Information

Aspect Ratio – A general quality criterion for mesh. High values signify the presence of deformed elements. While no exact threshold defines a good or bad mesh, a common practice is to aim for values below 100. If elements with high aspect ratios occur in regions with steep gradients, they may cause convergence issues. However, in areas of lesser significance, they might not affect accuracy or convergence.