Building the Mesh

This section describes the step-by-step procedure for preparing the mesh for the propeller simulation. The mesh is created using the General Mesher.

Select General Mesher in the Mesh Panel.
Select Advanced Mode for Setup Options.
Select CAD Surfaces propeller, propeller_side_mgi, propeller_front_mgi and propeller_back_mgi in the Geometric Entities Panel and click Add Surfaces icon for CAD Surfaces in the Properties Panel.
Ensure Relative to All CAD Surfaces is selected for Cell Size Specification.
Enter Maximum Cell Size as 0.01, Minimum Cell Size as 0.0001 and Cell Size on Surfaces as 0.01.
Select Yes for Refine Cells next to Boundary Cells.
Select Combined with Patches for Sub-feature Options.
Select Biggest Volume for Volume Options.
Click Create Mesh. A new mesh propeller is created under Built Meshes in the Geometric Entities Panel.
The meshed volume propeller is generated under Volumes.

Figure 8.90 - Propeller Mesh settings

Select General Mesher in the Mesh Panel.
Select Advanced Mode for Setup Options.
Select Exterior Volumes from the Mesh Location drop-down list.
Select all CAD Surfaces enclosure_front_mgi, enclosure_back_mgi and enclosure_side_mgi in the Geometric Entities Panel and click Add Surfaces icon for CAD Surfaces in the Properties Panel.
Select Nonuniform from Bounding Box Margins drop-down list and enter the values as follows:
- Minimum Side Sizes: 0.5,4,4
- Maximum Side Sizes: 1.5,4,4
Enter Maximum Cell Size as 0.1, Minimum Cell Size as 0.005 and Cell Size on Surfaces as 0.1.
Select Cylindrical Zone Refinement from Create a Refinement Zone drop-down list and specify the following parameters under Refine Zone Options extended list:
- Enter 0.025 for Cell Size
- Enter -1,0,0 for Top Circle Center
- Enter 3,0,0 for Bottom Circle Center
- Enter 0.5 as Zone Radius
Select Yes for Refine Cells next to Boundary Cells.
Select Biggest Volume for Volume Options.
Click Create Mesh. A new mesh enclosure is created under Built Meshes in the Geometric Entities Panel.
The meshed volume enclosure is generated under Volumes.

Figure 8.91 - Enclosure Mesh settings

Figure 8.92 - Propeller boundary mesh

Figure 8.93 - Section mesh

In this section, the Mismatched Grid Interfaces (MGIs) are generated between boundaries.

The steps to create the MGIs are as follows:

In the Geometric Entities Panel > Volumes > Boundaries, select Boundaries as shown in Table 8.1.
Click Connect Selected Boundaries via MGI icon to create the MGI entities. Refer, Figure 8.94.

A group display of entities can be viewed using the Group Entities by Volumes/Types icon at Geometric Entities Panel toolbar.

Connecting interfaces	Boundaries	Entity
Propeller and enclosure	enclosure_front_mgi and propeller_front_mgi	MGI01
Propeller and enclosure	enclosure_back_mgi and propeller_back_mgi	MGI02
Propeller and enclosure	enclosure_side_mgi and propeller_side_mgi	MGI03

Table 8.1 - Creating interfaces

The new entities are created under MGI in Volumes, refer Figure 8.95.

Figure 8.94 - Connecting Boundaries

Figure 8.95 - Created interfaces

Note: If MGIs are created by connecting the wrong boundaries, delete the created MGIs by clicking on Delete Selected Geometric Entity

icon and then recreate the MGIs.