Inflation is useful for CFD boundary layer resolution, electromagnetic air gap resolution or resolving high stress concentrations for structures. It is supported for the mesh methods listed in the section Inflation Group. You can use local inflation mesh controls to apply inflation to specific boundaries. When an inflation control is scoped to a solid model, every scoped geometry must have a boundary defined for it. The settings of the local inflation controls will override global inflation control settings.
You can define local inflation controls either by inflating a method or by inserting individual inflation controls.
Inflating a Method
Insert a mesh method.
Associate (scope) the desired bodies with the method.
Right-click the method and choose from the menu.
Note: For example, if you right-click a Tetrahedrons method control or a Sweep method control and specify the source, then an menu option is available. Choosing this option inserts an inflation control on every body to which the Tetrahedrons meshing method with the selected Algorithm is applied, or on every face to which the Sweep method is applied. Similarly, an inflation control will be inserted into the Tree Outline for each body/face. (Sweeping with inflation is the same as inflation with tetrahedrons except that with sweeping you pick faces and edges instead of bodies and faces.)
Highlight one of the inflation controls that was inserted into the Tree Outline.
Change the value of the Suppressed control if desired.
By default, the value of Suppressed is . If you change the value to , this inflation control has no effect on the mesh. In addition, an Active control with a read-only setting of appears under the Suppressed control when Suppressed is set to .
Use either of these methods to specify the inflation boundaries:
In the Details View, set Boundary Scoping Method to Geometry Selection, pick the entities in the Geometry window, and click the Boundary field in the Details View to Apply.
In the Details View, set Boundary Scoping Method to Named Selections, select a Named Selection from the Boundary drop-down, and press Enter.
Note:To select multiple Named Selections to be used as inflation boundaries, press and hold the Ctrl key while selecting the Named Selections from the Boundary drop-down, and then press Enter.
If none of the predefined Named Selections include the correct topology to be used as an inflation boundary, no Named Selections will be available in the drop-down. For example, if you scoped a surface body with the method in step 2, a Named Selection containing an edge must exist. Otherwise, you cannot select anything from the drop-down.
Specify additional inflation options as desired. For details about options, refer to the notes below and to Inflation Group.
Repeat steps 4 through 7 for each inflation control in the Tree Outline.
Inserting Individual Inflation Controls
Optionally, select the desired bodies or faces in the Geometry window.
Use either of these methods to insert the inflation control:
Click Mesh Control on the toolbar and choose from the menu.
Right-click in the Geometry window and choose > from the menu.
If you selected the bodies or faces in step 1, go directly to step 4. If not, use either of these methods to scope inflation to the desired bodies or faces:
In the Details View, set Scoping Method to Geometry Selection, pick the entities in the Geometry window, and click the Geometry field in the Details View to Apply.
In the Details View, set Scoping Method to Named Selection, and select a Named Selection from the Named Selection drop-down.
Change the value of the Suppressed control if desired.
By default, the value of Suppressed is . If you change the value to , this inflation control has no effect on the mesh. In addition, an Active control with a read-only setting of appears under the Suppressed control when Suppressed is set to .
Use either of these methods to specify the inflation boundaries:
In the Details View, set Boundary Scoping Method to Geometry Selection, pick the entities in the Geometry window, and click the Boundary field in the Details View to Apply.
In the Details View, set Boundary Scoping Method to Named Selections, select a Named Selection from the Boundary drop-down, and press Enter.
Note:To select multiple Named Selections to be used as inflation boundaries, press and hold the Ctrl key while selecting the Named Selections from the Boundary drop-down, and then press Enter.
If none of the predefined Named Selections include the correct topology to be used as an inflation boundary, no Named Selections will be available in the drop-down. For example, if you selected a face in step 1, a Named Selection containing an edge must exist. Otherwise, you cannot select anything from the drop-down.
Specify additional inflation options as desired. For details about options, refer to the notes below and to Inflation Group.
Notes on Defining Local Inflation Controls (2D Only)
In most cases, the controls in the global Inflation group apply to both 3D and 2D inflation, and the values set globally will be populated to the local inflation controls. Changes that you make to the local inflation settings will override the global settings. Exceptions and special considerations for defining 2D local inflation are described here.
When defining 2D local inflation, the available options for the Inflation Option control are (default), , and . If the Inflation Option control is set to or globally, it will be set to locally.
When Inflation Option is , you can set values for Transition Ratio, Maximum Layers, and Growth Rate.
If you select , you can set values for First Layer Height, Maximum Layers, and Growth Rate. The value of Growth Rate is used to calculate the heights of the successive layers, as follows:
Growth Rate = hn+1 / hn
where hn = height of layer n
If you select , you can set values for Number of Layers, Growth Rate, and Maximum Thickness. The first layer height is computed based on these three values. The heights of the successive layers are computed using the same formula shown above under .
When 2D inflation is applied to a 3D model (that is, to the face of a 3D body), the local value of Maximum Layers will be set equal to the global value by default. However, when it is applied to a 2D model (i.e, to the face of a surface body), the local value of Maximum Layers will be set to 2.
If you are using the Quadrilateral Dominant mesh method with inflation and the Size Function is on, the mesh size of the last inflation layer will be used for the corresponding Quadrilateral Dominant boundary mesh size.
Notes on Defining Local Inflation Controls (3D and 2D)
To make inflation boundary selection easier, select from the Toolbar and then deselect Body Scoping Annotations in the Annotation Preferences option box to toggle the visibility of annotations in the Geometry window. For example, after scoping inflation to a body, the body will be displayed using a blue solid annotation. Turn off the body scoping annotations, then select the desired faces as boundaries. For picking internal faces, the Hide Faces right-click option may help you to see inside a body. For example, you can select external faces in the Geometry window and then use the Hide Faces option to hide the selected faces (making it easier to select the internal faces).
Multiple Inflation controls can be scoped to the same body or face with different inflation options on the faces/edges.
If the mesh method is Automatic, the Patch Conforming tetrahedron method will be used for inflation on a body and the Sweep method will be used for inflation on a face.
If the mesh method is Cartesian (3D only) and Physics Preference is set to CFD, then three boundary layers are created with total thickness proportional to element size. If Cartesian and physics is not CFD, then a single boundary layer is added with thickness proportional to element size.
In the following scenarios, using inflation results in automatic suppression of the refinement control:
When automatic inflation (either Program Controlled or All Faces in Chosen Named Selection) is used with refinement in the same model
When local inflation is used with refinement in the same body or in the same part
For information on setting global inflation controls and descriptions of all of the individual inflation controls, refer to Inflation Group. For steps to follow to assign inflation depending on the selected mesh method, refer to Inflation Controls. For general information on applying inflation controls in combination with the various mesh method controls, refer to Meshing: Mesh Control Interaction Tables.