COMSOL 6.4 - Release from Grid

Use the node to release grains from a grid of initial positions with user-defined coordinates.

See Release for information about the following sections: and .

See the Release node for information about , , and .

Select an option from the list: (the default) or .

For and , enter based on space dimension (qx,0, qy,0, and qz,0 for 3D components) for the grain positions, or click the button (

) to select and define a range of specific coordinates.

If is selected, the number of initial coordinates entered for each space dimension must be equal, and the total number of grains released is equal to the length of one of the lists of initial coordinates. If is selected, the total number of grains released is equal to the product of the lengths of each list of initial coordinates.

For example, suppose a 2D model component includes a node with the following initial coordinates:

If is selected, a total of 16 grains will be released, including every possible combination of the initial x- and y-coordinates. If is selected, 4 grains will be released with initial positions (0,2), (1,4), (2,6), and (3,8).

The position for any grains with initial coordinates outside the geometry are set to not-a-number (NaN), so the grains do not appear when plotted during results processing.

In the section, click the

and

buttons to visualize the initial grain positions. Clicking causes a point to appear in the window for every release position. Clicking causes a bounding box to appear, indicating the spatial extents of the released grains. Examples are shown in Figure 3-1 and Figure 3-2.

Choose the desired set of grain properties described in one of the nodes from list. The default is the first node in the node tree.

By default, grains will be released at the initial positions only if they do not interact with any existing grains or with the walls. This can be controlled by the checkbox which is selected by default. When enabled, enter a nonnegative value or expression for the (SI unit: m). The default is 0 m. This value is used to control the amount of acceptable overlap. When the checkbox is not selected, grains are always released at the specified coordinates irrespective of the overlap with other grains and wall elements.

If is selected from the list in the physics interface section, the field is available. Enter the seed value of the pseudorandom number generator (PRNG) used by this feature. The default value is 1. The PRNG is used to generate random numbers for sampling grain release times, positions, grain properties, and initial values of auxiliary dependent variables.