The range for orthogonal quality is 0-1, where a value of 0 is worst and a value of 1 is best.
The orthogonal quality for cells is computed using the face normal vector, the vector from the cell centroid to the centroid of each of the adjacent cells, and the vector from the cell centroid to each of the faces.Figure 69: Vectors Used to Compute Orthogonal Quality for a Cell (p. 135) illustrates the vectors used to determine the orthogonal quality for a cell.
Figure 69: Vectors Used to Compute Orthogonal Quality for a Cell
The orthogonal quality for a cell is computed as the minimum of the following quantities computed for each face i:
⋅
ur ur ur ur
where
ur u
is the face normal vector and
u r
is a vector from the centroid of the cell to the centroid of that face.
and
⋅
ur ur ur
ur
where
is a vector from the centroid of the cell to the centroid of the adjacent cell that shares the face.
Note
• When the cell is located on the boundary, the vector
u r
across the boundary face is ignored during the quality computation.
• When the cell is separated from the adjacent cell by an internal wall (e.g., a baffle), the vector
u r
across the internal boundary face is ignored during the quality computation.
• When the adjacent cells share a parent-child relation, the vector
u r
is the vector from the cell centroid to the centroid of the child face while the vector
u r
is the vector from the cell centroid to the centroid of the adjacent child cell sharing the child face.
The orthogonal quality for faces is computed using the edge normal vector and the vector from the face centroid to the centroid of each edge.Figure 70: Vectors Used to Compute Orthogonal Quality for a Face (p. 136) illustrates the vectors used to determine the orthogonal quality for a face.
Figure 70: Vectors Used to Compute Orthogonal Quality for a Face
The orthogonal quality for a face is computed as the minimum of the following quantity computed for each edge i:
where
ur u
is the edge normal vector and
u r
is a vector from the centroid of the face to the centroid of the edge.
Note
Orthogonal quality in the Meshing application (and ANSYS FLUENT) is equivalent to orthoskew in TGrid, except that the scale is reversed:
Orthoskew = 1 – Orthogonal Quality
The orthoskew values may not correspond exactly with the orthogonal quality values as the computation depends on boundary conditions on internal surfaces (WALL vs. INTERIOR/FAN/RA-DIATOR/POROUS-JUMP). ANSYS FLUENT may return different results which reflect the modified mesh topology on which CFD simulations are performed. Also, for CutCell meshes, the ele-ments in the Meshing application are “traditional” (hex/tet/wedge/pyramid) eleele-ments. When a CutCell mesh is exported from the Meshing application to ANSYS FLUENT, elements that are connected to parent faces are exported in polyhedral format, while all others retain their type. Note that this behavior is only true for the CutCell assembly algorithm; the Tetrahedrons assembly algorithm uses only traditional element types.
Local mesh controls are available when you highlight a Mesh object in the tree and choose a tool from either the Mesh Control drop-down menu, or from first choosing Insert in the context menu (displayed from a right mouse click on a Mesh object). You can specify the scoping of the tool in the tool's Details View under Method to either a Geometry Selection or to a Named Selection.
Note
Be aware of the following items regarding mesh control tools:
• The Object Generator enables you to make one or more copies of a template object, scoping each to a different piece of geometry. When defining mesh controls, you can use the Object Generator to make copies of a template mesh control, which may reduce the necessity to manually define multiple related mesh controls. For details, refer to Generating Multiple Objects from a Template Object in the Mechanical help.
• For most mesh controls, the latest control that you add on a particular geometry overrides any prior controls that you already have added on that geometry. For example, if you apply a Sizing control setting of 0.5 to faces A,B,C then apply a setting of 1.0 to face B, faces A and C will retain the 0.5 setting, but the setting for face B will be 1.0. This is also useful when you want to force sweep many bodies of a multibody part and only tet mesh one or specify special sweeping options on one. For example, you can select all 1000 parts and then override one or 10 part(s) instead of picking 999 (990) and then selecting one (10).
Exceptions include the MultiZone Quad/Tri, MultiZone, and All Tetrahedrons - Patch Inde-pendent controls. For information about how these controls interact with other controls, refer to "Meshing: Mesh Control Interaction Tables" (p. 333),Interactions Between Mesh Methods (p. 333), and Interactions Between Mesh Methods and Mesh Controls (p. 336).
• If you suppress a mesh control tool, the Suppress symbol appears ("x" adjacent to the name of the tool) and Suppressed is set to Yes in the Details View of the tool. Situations can occur when you do not suppress a mesh control tool, and the Suppress symbol appears adjacent to the tool but Suppressed is set to No in the Details View of the tool. In these situations, refer to the mesh control's Active read-only field for the reason why the tool is suppressed. Examples are a control applied to a uniform surface body mesh (not supported), a control scoped to suppressed geometry, or a Contact Sizing control scoped to a suppressed Contact Region.
The following local mesh controls are available:
Method Control
Pinch Control Inflation Control Sharp Angle Tool Gap Tool