Release from Data File
Use a Release from Data File node to release grains by specifying the initial position, velocity, and values of auxiliary dependent variables using data from a text file.
See Release for information about the following sections: Release Times and Initial Value of Auxiliary Dependent Variables.
See Release from Grid for information about the following sections: Released Grain Properties and Advanced Settings.
Formatting Guidelines for Files Containing Grain Data
The imported data file should be a text file (*.txt) arranged in a spreadsheet format; that is, each row corresponds to a distinct grain and should have the same number of columns as all other rows. Columns can be separated by spaces, tabs, or a combination of the two. Begin a line with the percent (“%”) character to include comments or empty lines in the data file.
For example, a data file containing the following text would insert grains at the positions (0.1, 0.2, 0.6) and (0.2, 0.4, 0.8) in a three-dimensional geometry:
% Initial grain positions
% qx0 qy0 qz0
0.1 0.2 0.6
0.2 0.4 0.8
Initial Values
See the Release node for information about Angular velocity in body-fixed frame and Temperature.
Filename
Browse your computer’s file system to select a text file, then click Import to import the data. To remove the imported data, click Discard. Enter the Index of first column containing position data i to indicate which column represents the first coordinate of the grain position vectors. The default value 0 indicates the first column.
Velocity
Select an option from the Initial velocity list: From file, or User defined (the default).
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For From file, enter the Index of first column containing velocity data i. The default is 3 in 3D and 2 in 2D. The columns are zero-indexed; that is, an index of 0 corresponds to the first column. Select the Rotate velocity vectors checkbox to rotate the velocity vectors using the specified Euler angles (Z-X-Z) in 3D or Rotation angle in 2D. The checkbox is cleared by default.
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For User defined, enter values or expressions for the Initial grain velocity v0 (SI unit: m/s) based on space dimension. The defaults are 0 m/s.
Transformations
The distribution of loaded grain positions can be scaled, rotated, and translated before the grains are released.
To scale the distribution of release positions, enter a value or expression for the Scale factor R (dimensionless). The default is 1. This scale factor can be used to correct unit discrepancies between the data file and the model geometry. For example, if the geometry length unit is in meters but the data file lists coordinates in millimeters, enter a scale factor of 0.001.
To rotate the distribution, enter the Euler angles (Z-X-Z) α, β, and γ (in 3D) or the Rotation angle α (in 2D). The default values are all 0.
In 3D, α is the rotation angle about the space-fixed z-axis, then β is the rotation angle about the transformed x-axis (or x'-axis), and finally γ is the rotation angle about the transformed z-axis (or z''-axis). Positive values indicate counterclockwise rotations.
Enter values or expressions for the components of the Displacement vector Δq (SI unit: m). The default is not to apply any translation.
If a translation and another type of transformation (scaling or rotation) are applied, then the translation is always applied after the other transformations.