Creation of an isolated turbulent blob sustained by vortex ring injection

We experimentally study a steady, localized blob of turbulence, sustained by the collision of multiple vortex rings. Through PIV and 3D PTV, our measurements reveal that the blob consists of a turbulent core surrounded by comparatively quiescent fluid. We examine the transport of mass, energy, and enstrophy to elucidate the formation of the confined turbulence. The turbulent intensity and geometry of the blob could be fully tuned by altering the properties of the injected vortex rings. Our work paves the way to sculpt turbulence at a target location with a controlled injection of energy, enstrophy, and helicity.