Moving Regions

Defining a moving region

Moving regions usually belong to the sample cartridge assembly (SCA) and require time-dependent computation (full implicit time model). You specify either constant velocities in radial (r) or axial (z) direction or you specify a file containing time-dependent position or velocity profiles. The file must be a text file with the extension *.mov and has to correspond to the following format:

Time (col. 1)

r-coordinate (col. 2)

z-coordinate (col. 3)

0

0.

0.

100

0.

0.

500

0.

0.5

1000

0.

0.5

In this example the region will not move at all in the interval from 0 to 100 seconds. Then the region will move 5 cm in z-direction within the next 400 seconds and remain in this position until 1000 seconds have elapsed.

The program will take the information about the position from columns 2 and 3 for the first moving region. In the dialog you only specify the column of the r-coordinate, the program takes the next column automatically as z-coordinate. If you want to specify time profiles for more than one moving region in the profile file, you add column 4 and 5 for the second moving region, 6 and 7 for the third and so on.

If you want to specify time-dependent velocity profiles, the *.mov file has a similar format, but instead of coordinates you have to write the values of r and z-velocity.

The following prerequisites should be considered when working with moving regions:

Pay attention, that the sliding line between the moving regions and environment should be directed parallel to the movement vector.

The distortion of the neighbor regions attached with the moving region can be avoided by introducing a label at the shared line, along which slides the moving region.

Open the dialog Labels , select the sliding line and mark it as Sliding . For details see section Labels and Joiner. The labeled line will remain unmovable, the moving region will slide with respect to it.

Note

If the only line at side of the unmovable regions is attached to the sliding boundary, then an additional line can be introduced in Geometry mode in order to create the second vertex at the sliding line. The line between these two vertexes can be then labeled as described above and the distortion of the geometry around moving regions will be avoided.