The above diagram is derived from the dipole gravity potential expressed below by setting the latitude angle theta equal to zero for the positive Z axis and 180 degree for the negative Z axis, where the form factor etha is introduced to smooth out the sharp singularities which are considered mathematical artifacts.
At the poles of the rotating sphere, the dipole potential indicates the existence of linear trajectories along the rotation axis.
This dipole potential at the poles looks like a funnel if it is viewed in the three dimensional picture. The angular distribution of the potential that produces jets spreads out as the distance increases further away from the center.
From this observaiton, it is expected that particles going into the rotating black hole through the poles of the rotation axis actually have much higher probability of going through a rapid spiraling motion instead of a straight through linear trajectory, which will be the same for the particles coming out.
This picture provides an explanation on why not all the particles going in and out collide each other head on, only to reduce the net stream to zero in a short period of time.
However, the diagram shows clearly that there are possibilities of the matter spilling over from the central harmonic potential region to the side ways when the density of matter exceeds the limit of its capacity within the limited space.
As soon as they cross over the shallow potential hill, there is a deep and powerful fall that pushes them out of the rotation axis.
Also, the observed jets certainly indicates violent collisions of matters along the rotation axis.
If the jets are formed by uniformly outgoing particles only, the observed radiation would be hard to explain.
Note: The longitudinal component of the dipole gravity force in the above diagram needs to be corrected, although the major properites may not be affected, the sign of the force has to be reversed. This issue is discussed in detail in the following "Sign Error in Lens-Thirring Force?" page.