Irrotational flow
In vector calculus a conservative vector field is a vector field that is the gradient of some function, known in this context as a scalar potential. Conservative vector fields have the property that t...
Irrotational flow - Wikipedia
Vorticity
In continuum mechanics, the vorticity is a pseudovector field that describes the local spinning motion of a continuum near some point (the tendency of something to rotate ), as would be seen by an obs...
Vorticity - Wikipedia