Vortical
In
fluid dynamics, the movement of a fluid can be said to be
vortical if the fluid moves around in a circle, or in a helix, or if it tends to spin around some axis. Such motion can also be called
solenoidal.
Vortical movement is characterized by non-zero curl:
-
i.e.
- ,
where
v is the velocity vector field of the fluid.
The curl of the velocity (at a specified point of the vector field) yields a vector (or actually a pseudo-vector) which points in the direction around which the fluid is rotating. In this way it is similar to the eigenvector of a rotation matrix.
See also: vortex, vorticity.