If we look at examples of physics on earth we note that the phenomenon of tornados and hurricanes result from movement of heat. Aslo eddies and whirlpools are caused by turbulence. This movement of energy coupled with rotation and gravitation factors create spiraling.
As I look at models of blackholes and add to that the fact that they are active and then passive it seems logical that blackholes
are of two types 1-passageways for energy moving from an area of higher concentration to lower concentration and 2-byproducts
of 2 or more masses colliding and producing cosmic whirpools.
As the energy disipates the mechanism stalls.