StarCCM+ Directed/Structured Mesh

The information in this section has been presented by Micheal in Nov '17.
Corresponding slides can be found here: Introduction to Directed Mesh

What is directed mesh

It is a meshing method used to generate high quality structured grids

Also called Sweep,Extruded, or Structured mesh

It operates by sweeping a mesh from a source surface to a target surface through a guide surface. (at least 3 surfaces are required)

Advantages:

  • Lower number of neighbor-cells compared to polyhedral grid
  • Faster computations compared to polyhedral grid

Important requirements for the CAD geometry!

Each part must have at least three surfaces, representing the source, target, and guide surfaces

There cannot be any features intruding into the sweep path (the guide surface)

For Multi-parts, Imprinting the contacting parts on each other is essential

Main steps

  1. Draw/Import the 3D CAD geometry
  2. Create a new geometry part
  3. Assign the geometry part to a region
  4. Right click the Operations under Geometry tap and select New then Directed Mesh
  5. Right-click Operations > Directed Mesh node and choose Edit
  6. Choose source and target surfaces for each connected part
  7. Create the starting mesh on the source surface by Patch Mesh, Use Existing Mesh, or Automatic Source Mesh
  8. Define a volume distribution (no. of layers)
  9. Generate the volume mesh

Creating the source surface mesh

There are three options for the source mesh!

option example
Patch Mesh
Existing Mesh
Automatic Source Mesh

Examples

Rectangular Prism Geometry with automatic source mesh

Automatic Source Mesh Without Prism Layer With Prism Layer
Polys
Quads
Tetras

Rectangular Prism Geometry with structured source mesh

Source Mesh Block structure Mesh
Patch mesh
Patch mesh
with near wall refinement
Patch mesh
with O-Grid

Pipe Geometry

Source Mesh Block structure Mesh Iso view
Patch mesh
Patch mesh
with near wall refinement
Patch mesh
with near wall refinement
and smoothing

More examples & Supplementary Files

Structured 2D mesh

This video shows how to create a 2D structured mesh with a Directed Mesh, but without using the “Convert to 2D” feature. The example presented is a typical domain around an airfoil, where usually a C-type topology is chosen for the mesh. The Directed Mesh setup is the same as in 3D structured mesh generation, but the pipeline result is a directly 2D mesh because a “Badge for 2D Meshing” operation is executed first. Therefore the number of mesh layers in the Z direction can be set to 1.

The same concept holds for the creation of a 2D trimmed mesh, which is shown in another video below. The procedure explained is pipelined, but it cannot be automatically re-executed following a geometrical change, as the patching structure is defined manually.

Source: https://thesteveportal.plm.automation.siemens.com/VideoLibrary#/articles/en_US/Video/How-to-create-a-structured-2D-mesh-inside-STAR-CCM

Trimmed cell 2D mesh

In this video, you learn how to get a 2D pipelined trimmed mesh on a simple airfoil problem. The airfoil geometry is imported in the 3D-CAD modeler of STAR-CCM+ and its angle of attack is made parametric. A 2D trimmed mesh is generated with parts operations, without breaking the pipeline - that is, avoiding the use of Mesh > Convert to 2D.

The setup and quick run of the simulation is shown, along with the pressure field contour and the lift force monitor plot. Then the airfoil angle of attack is changed and the pipeline automatically re-executed. By proceeding with the run, the changes of flow field and lift are shown.

Source: https://thesteveportal.plm.automation.siemens.com/articles/en_US/Video/How-to-create-a-mesh-pipeline-with-a-2D-trimmed-mesh


guide/starccm/directedmesh.txt · Last modified: 2018/06/11 13:58 by seengel
Back to top
CC Attribution-Share Alike 3.0 Unported
chimeric.de = chi`s home Valid CSS Driven by DokuWiki do yourself a favour and use a real browser - get firefox!! Recent changes RSS feed Valid XHTML 1.0