Editing Vorticity (section)

== Evolution ==
The evolution of the vorticity field in time is described by the [[vorticity equation]], which can be derived from the [[Navier–Stokes equations]].<ref>Guyon, et al (2001), pp. 289–290</ref>

In many real flows where the viscosity can be neglected (more precisely, in flows with high [[Reynolds number]]), the vorticity field can be modeled by a collection of discrete vortices, the vorticity being negligible everywhere except in small regions of space surrounding the axes of the vortices. This is true in the case of two-dimensional [[potential flow]] (i.e. two-dimensional zero viscosity flow), in which case the flowfield can be modeled as a [[complex number|complex-valued]] field on the [[complex plane]].

Vorticity is useful for understanding how ideal potential flow solutions can be perturbed to model real flows. In general, the presence of viscosity causes a [[diffusion]] of vorticity away from the vortex cores into the general flow field; this flow is accounted for by a diffusion term in the vorticity transport equation.<ref>{{cite book |first1=Kip S.|last1=Thorne|first2=Roger D.|last2=Blandford|author-link1=Kip Thorne|title=Modern Classical Physics: Optics, Fluids, Plasmas, Elasticity, Relativity, and Statistical Physics|publisher=Princeton University Press|year=2017|isbn=9780691159027|page=741}}</ref>