Circulation Of Velocity

Circulation of velocity – the line integral of the second kind, taken over an arbitrary closed contour γ.

If the circulation of velocity along any closed circuit drawn inside the liquid is zero, then the flow of the liquid will be a potential flow and the potential of the velocities will be a unique function of the coordinates. If the circulation of velocity along some contours is different from zero, the flow of the fluid will be either vortex in the corresponding regions, or vortex-free, but with an ambiguous velocity potential. In the latter case, the circulation of velocity along all contours covering the same borders has the same value. The circulation of velocity is widely used as a characteristic of the flow of an ideal fluid. For a viscous liquid, the circulation of velocity is always different from zero and changes over time due to the diffusion of eddies.

Sources:

Science News For Students https://www.sciencenewsforstudents.org/article/

Britannica https://www.britannica.com/science/