COMSOL 6.2 - Distribution

It is possible to add nodes both as global nodes and as local nodes. If there are several nodes in the sequence with a nonempty selection intersection, the mesher uses properties corresponding to the last node in the sequence for each selection of entities. properties always override properties defined by nodes sharing the same selections.

To add a attribute as a global node, select edges (3D) or boundaries (2D) and choose one of the following:

To add a attribute as a local node, select edges (3D) or boundaries (2D) and choose one of the following:

	Global vs. Local Attributes.

Define the geometric entities where you want to specify a distribution. Choose from the list to select the entities in the window or choose to select all available entities of that level.

Choose the level of the geometry from the list (only available for global attributes in 3D):

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Choose to specify the domains for the distribution. Choose in the list to select the domains in the window, choose a named selection to refer to a previously defined selection, or choose to select all domains.

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Choose to specify the edges for the distribution. Choose from the list to select the edges in the window, choose a named selection to refer to a previously defined selection, or choose to select all edges.

	The name of this section changes depending on the dimension of the component. The names are Edge Selection (local attributes in 3D), Boundary Selection (2D), or Domain Selection (1D and 3D), respectively. For global attributes in 3D, the name is Geometric entity level.

There are three main types of distribution methods that you select from the list:

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Select to use an explicit, user-defined element distribution. To define the distribution of mesh elements, enter a vector-valued expression defining a strictly increasing sequence of nonnegative numbers (using comma-separated numbers) in the field, specifying the relative arc length values of the mesh vertices along the edge or boundary. Select the check box to reverse the direction of the explicit distribution.

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Select (default) to use a fixed number of mesh elements, which you enter into the field. Select the check box to generate equally sized elements along the selected edges (3D) or boundaries (2D). The check box is only available for edge and boundary selections.

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Select to specify properties of a predefined distribution method that can be either an exponentially or a linearly increasing or decreasing element size; see below for details. See Figure 8-50 for an example of a predefined exponential distribution.

In the field, enter the number of elements (the default is 5 elements). To specify the ratio in size between the last element and first element in the distribution, use the field (the default value is 1.0; that is, the first and the last elements have the same size). From the list, select for an element distribution based on an arithmetic sequence or select for an element distribution based on a geometric sequence. Select the check box to get a symmetric distribution of elements. The will then define the ratio between the element in the middle of the distribution and the last element. Select the check box to switch the element distribution to the opposite direction along the edge or boundary. If you have specified several edges in the selection, the check box refers to the edge in the selection with the lowest entity number (the primary edge). For the other edges, their direction (with respect to the distribution) is such that the rotation with respect to the primary edge is minimized.