Slipstreams

Slipstreams, also known as vortex rings or toroidal vortices, are a phenomenon observed in fluids, most commonly air or water. They consist of a torus-shaped region in which a fluid is spinning in a circle. The fluid moves down through the center of the ring and up around the outside. This self-contained motion allows the ring to travel a significant distance without dissipating quickly.

Slipstreams are created when a fluid is ejected from an opening in a specific manner. For example, a puff of smoke from a cigarette or a jet of air from a specialized cannon can form slipstreams. The shape and stability of the slipstream depend on factors such as the velocity of the fluid, the size and shape of the opening, and the properties of the fluid itself. In some cases, multiple slipstreams can interact, leading to complex fluid dynamics.

These vortex rings have applications in various fields. In nature, they can be observed in the wake of moving aquatic animals or birds, potentially reducing drag. Scientists study slipstreams to understand fluid mechanics and have explored their use in areas like acoustic levitation and the transport of small objects. The visual appearance of slipstreams, often seen as rings of smoke or bubbles, makes them a striking example of fluid motion.