Remove Invalid Cells

This operation accesses the Remove Invalid Cells action available on regions. You can choose one or more criteria with which to identify poor quality cells. See Removing Invalid Cells.

Properties

Regions

Select the regions in which to remove invalid cells.

Check Face Validity

The face validity is an area-weighted measure of the correctness of the face normals relative to their attached cell centroid. For more details, refer to Face Validity.

The suggested minimum threshold value is 0.51-0.95 (default 0.51).

Check Cell Quality

The cell quality metric algorithm is based on a hybrid of the Gauss and least-squares methods for cell gradient calculation. Generally, flat cells with highly non-orthogonal faces have a low cell quality. For more details, refer to Cell Quality.

The suggested minimum threshold value is 1e-05 to 1e-12 (default 1e-08).

Check Volume Change

The volume change metric describes the ratio of the volume of a cell to that of its largest neighbor. For more details, refer to Volume Change.

The suggested minimum threshold value is 1e-05 to 1e-12 (default 1e-10).

Check Contiguous Cells

The contiguous cells metric is used to identify discontiguous regions of cells. These cell regions can either pre-exist in the volume mesh or be created when bad quality cells are removed based on other invalid cell criteria. Discontiguous cells would cause the solver to fail.

A value in the range 1 to 1000000 can be entered. This value indicates the number of cells in the discontiguous region. By default it is set to 1. See Contiguous Cells.

Check Connected Face Area Value

The connected face area is the smallest area that is allowed between two connected cells, below which the cells would be considered discontiguous and subject to the contiguous cells check criterion.

This value is dependent on the case dimensions and can be estimated based on the average mesh cell size. By default it is set to 0.0. See Connected Face Area.

Check Volume

The volume metric defines the minimum cell volume value. All the cells with volume below this value will be removed.

You can specify any value above or equal to zero. By default it is set to 0.0.

Function

The function metric allows you to remove the cells for which a selected field function has a value below or above a specified limit.

To specify the field function, click <Select Function> in the Function group box and use the Select Objects dialog.

Function Operation

The function operation defines the operator (>) or (<) in order to select the cells with the value larger or lower than the [Function Threshold] respectively.

Function Threshold

The function threshold is value of the field function Function above or below which cells are removed.