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Pre-Processing
Simcenter STAR-CCM+ solves physics problems on a computational mesh. To provide this mesh, you first define geometry using internal or external tools, and then create a mesh pipeline whose operations generate the mesh in repeatable steps.
Meshing
A mesh is a discretized representation of a geometric domain. This domain can include real-world geometry, its content, and its surrounding environment.
Surface Meshers
Simcenter STAR-CCM+ contains meshing tools which can be used to help prepare a high-quality surface mesh before a volume mesh can be generated.
Surface Remesher
In order to improve the overall quality of an existing surface and optimize it for the volume mesh models, the surface remesher can be used to retriangulate the surface.
Surface Remesher with Interfaces
In order to achieve a conformal mapped mesh at the interface, the surface remesher can be used with specific direct type interfaces.

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Pre-Processing
Simcenter STAR-CCM+ solves physics problems on a computational mesh. To provide this mesh, you first define geometry using internal or external tools, and then create a mesh pipeline whose operations generate the mesh in repeatable steps.
- 3D-CAD
  3D-CAD is a feature-based parametric modeler within Simcenter STAR-CCM+ that allows you to build geometries from scratch. The geometries that you create with 3D-CAD are stored as 3D-CAD models, which you can then convert to geometry parts for integration with the meshing and simulation process.
- Modeling Geometry
  This part of the User Guide describes how to use 3D-CAD, the parametric solid modeler available within Simcenter STAR-CCM+. It also describes the features and tools available for further preparation of the geometry model and its surfaces.
- The Surface Repair Tool
  The Surface Repair tool diagnoses errors in, and provides repair tools for, tessellated surfaces and part curves. The same tool allows you to reorganize discretized geometry by searching for face-based features and attributes then assigning the results to new or existing part surfaces or curves.
- Defining the Regions Layout
  An essential part of the process in setting up your simulation is to define the relationship between geometry parts and regions, boundaries, and interfaces.
- Meshing
  A mesh is a discretized representation of a geometric domain. This domain can include real-world geometry, its content, and its surrounding environment.
  - Mesh Construction
    Within a bounding volume defined by geometrical surfaces, Simcenter STAR-CCM+ can construct meshes for finite volume and finite element solvers.
  - Meshers in Simcenter STAR-CCM+
    The meshers in Simcenter STAR-CCM+ generate surface and volume meshes for geometry parts that are assigned to regions and make them ready for analysis.
  - Parts-Based Meshing
    Parts-based meshing (PBM) is a meshing strategy in which you create one or more mesh operations that define workflows for preparing, fixing, and processing geometry. A major benefit of PBM is that every mesh operation you create forms part of a linear and repeatable process.
  - The Meshing Workflow
    This section contains the recommended workflow for setting up and generating the volume mesh at the parts level.
  - Mesh Operations
    Mesh operations perform actions on geometry parts that you can easily repeat whenever their input parts or properties are changed.
  - Mesh Descriptions
    A mesh description is a version of a surface or volume mesh belonging to a geometry part. Geometry parts can have more than one surface mesh description associated with them. You create and change descriptions by importing surfaces or executing operations.
  - Custom Mesh Controls
    Custom controls override any default controls for the surface and volume meshers. This facility allows you to refine or coarsen the mesh for part curves, part surfaces, geometry parts, and specified volumes.
  - Surface Meshers
    Simcenter STAR-CCM+ contains meshing tools which can be used to help prepare a high-quality surface mesh before a volume mesh can be generated.
    - Surface Meshers Overview
      This section provides a comparison of the Surface Remesher and Surface Wrapper
    - Surface Wrapper
      The Surface Wrapper can be used to provide a closed, manifold, non-intersecting surface when starting from poor quality CAD data.
    - Surface Remesher
      In order to improve the overall quality of an existing surface and optimize it for the volume mesh models, the surface remesher can be used to retriangulate the surface.
      - Aligned Meshing and Geometric Features
        In the surface remesher, aligned meshing is a fully automated process which creates a template mesh on surfaces with four corners.
      - Surface Remesher with Interfaces
        In order to achieve a conformal mapped mesh at the interface, the surface remesher can be used with specific direct type interfaces.
      - Surface Remesher Guidelines
        This section provides guidelines for using the Surface Remesher.
      - Surface Remesher Reference
        You can control the remeshing process using the properties and right-click actions for the Surface Remesher node. The properties include the meshing method and refinement options.
    - Geometric Sensitivity
      The Geometric Sensitivity mesher allows you to calculate and visualize how sensitive a 3D-CAD model or CAD Client model is to the adjustment of specific shape parameters. The mesher applies an offset to the specified parameters and calculates how sensitive the surface is to changes in the parameter for each face on the surface, using a finite difference approximation.
    - Automatic Surface Repair
      The Automatic Surface Repair operation provides an automatic procedure for correcting a range of geometric type problems that can exist in the remeshed surface once the surface remeshing process is complete.
    - Surface Mesher Controls and Values
      This section details the controls and values for all surface meshers.
  - Volume Meshers
    Simcenter STAR-CCM+ contains different types of meshers that can be used to generate a volume mesh starting from a suitably prepared surface mesh.
  - Mesh Refinement
    Simcenter STAR-CCM+ can refine the mesh by approximating the wake region or using solution-based approach. These features allow you to achieve efficient refinement by reducing the cell size in areas of interest.
  - Directed Meshing
    Directed meshing is a method for generating high quality swept meshes on geometries in Simcenter STAR-CCM+. The method operates by sweeping a mesh from the surfaces of a geometry through its volume onto a facing target surface.
  - Two Dimensional and Axisymmetric Meshes
    The use of a one-cell-thick three-dimensional mesh is much less efficient than using a real two-dimensional mesh for two-dimensional and axisymmetric simulations. When circumstances allow, use real two-dimensional meshes.
  - Turbomachinery Mesh
    Turbomachinery applications with axial blades typically require a flow-aligned, structured mesh. This type of mesh has implicit connectivity and a fixed number of vertex or face neighbors, leading to a more accurate solution.
  - Mesh Visualization
    You can visualize any mesh representation in Simcenter STAR-CCM+. After you have imported or generated a mesh, you visualize it to check the cell quality and mesh validity.
  - Checking the Surface Mesh
    The volume mesh quality is directly dependent on the surface mesh quality. Therefore, it is crucial to make sure that all surface meshes are of good quality.
  - Checking the Volume Mesh
    This section describes the tools available for checking the validity and quality of the volume mesh, and for diagnosing problem areas. Such problems can then be fixed, either inside Simcenter STAR-CCM+ or in the originating mesh generator.
  - Meshing Field Functions Reference
    This section contains a list of field functions that are related to meshing.
  - Working With Representations
    This section provides information on representations as a useful part of the meshing process.
  - Scaling the Entire Mesh
    Scaling the mesh is important as the units of the model must be in meters before running an analysis.
  - Working with Baffles
  - Exporting Mesh and Solution Data
    This section outlines the steps for exporting Simcenter STAR-CCM+ mesh and solution data to formats that can be used in other CAE packages.
  - Multi-Region Meshing
    This section outlines the surface requirements for performing multi-region meshing, as well as step-by-step instructions when starting from surface imports that result in single region and multiple regions definitions. Additionally, guidelines are provided on what the best approaches are for exporting surface data from CAD packages when multiple regions are required.

Surface Remesher with Interfaces

In order to achieve a conformal mapped mesh at the interface, the surface remesher can be used with specific direct type interfaces.

This recommended procedure results in a better volume mesh definition for the analysis.

For an in-place type interface, a conformal mesh can be obtained for both single region and multi-region cases, as long as the same mesh operation is used. For example, in a single region case, an in-place interface can be used to represent an internal baffle of some kind. For multi-region cases, the interface can represent a change of material, such as a fluid/porous interface or fluid/solid of some kind. Additionally, the surface remesher can now be used regardless of the perimeter shape of the boundaries at the interface as long as the interface boundaries are planar. In other words, the boundaries belonging to the interface do not need to have the same shape or area. An imprint method is automatically included as part of the surface remeshing process, meaning that the boundaries are first retriangulated to have a common perimeter before proceeding with the surface remeshing step.

When the surface remesher is used with a periodic interface, then it attempts to produce a conformal mapped mesh for the boundary pair. Both boundaries have to belong to the same region in this instance.

When using one of the above direct type interfaces for surface remeshing, then the interface node controls the settings and sizes that are common to both boundaries. Where remainder boundaries exist for in-place type interfaces (that is, those that belong to a boundary that is part of an interface but is not common to the boundary pair), the normal boundary node settings and sizes are used instead.

When visualizing the remeshed surface, include the interface boundary nodes that are connected to the boundary pair in the displayer parts selection so that the mesh triangulation can be seen on those faces. The interface boundary surfaces are also colored according to their type.

When using the repeating type interface, a conformal mesh interface is not required because the meshes in each region are sliding past each other. Here the per-region meshing option must be activated in order to ensure a good quality surface at the interface.

Additional notes on surface remeshing with interfaces are provided in the guidelines section.