Details

When , the spheres are packed in a straight line. The line joining the centers zigzags as the tube diameter increases until , at which point the spheres are stacked in two columns.

For only spheres, the angle between the axis of the channel and center to center of spheres is:

.

For spheres and spacers, the angle between the axis of the channel and center to center of spheres is:

.

The center-to-center distance of the two spheres is:

.

The compression ratio is:

.

The force input-output model is represented by the equations:

,

.