How do you set up a nested rotation in CFX-10.0?
In general, specifying a rotating domain inside a rotating domain in CFX-Pre does
not move the axis of the rotated domain. This needs to be done as a moving mesh case.
Let's say that a larger outer cylinder is spinning around a global z axis and smaller inner
cylinders are rotating around their own local z axis (as well as around a global
z axis). Then the solid body rotation of the large cylinder needs to be defined
as a moving mesh and the local rotation of smaller cylinders as a number of individual
The larger cylinder needs to be connected to the surrounding stationary domain by a
standard GGI interface which will automatically update the reintersecting moving mesh.
The smaller (inner) rotating cylinders must be connected to the larger (outer) cylinder by
transient rotor-stator interfaces. Defining an interface, creates two separate BCs patches,
one for each domain. These patches need to move with the same mesh displacement as the
volume mesh of the larger (outer) cylinder, therefore mesh motion has to be defined for
them as well.