Taylor Column

When moving fluid comes into contact with a submerged object, it forks in two and flows around the object. But if the fluid is moving in a circle and rotating, something strange happens: the submerged object creates a "cylinder" of still water that extends from the top to the bottom of the fluid, well above the physical height of the object.

This "virtual" cylinder is known as a Taylor column and can disrupt the flow of water just as if it were a physical column.



credit: Semple/Moore/University of Toronto


This phenomenon in encountered in an amazing range of scenarious and scales, essentially whereever moving or rotating fluids are involved, for example in industrial processes, ocean currents, atmospheric phenomenon like winds, etc.

This phenemenon is named after the British physicist Geoffrey Ingram (G. I.) Taylor (1886–1975), who deviced experiments to study and provided mathematical explanations of this and many other hydrodynamics observations.

Taylor's experiment consisted of a rotating cylindrical tank of fluid. The tank is rotated at a high frequency. Once the fluid settles into solid-body rotation, a small cylinder (a fraction of the height of the fluid) is dragged along the bottom of the tank. Dye is then injected into the fluid. In a non-rotating tank, the dye is free to move anywhere in the fluid. However, in the rotating tank, the dye would be diverted from passing over the cylinder as if the cylinder's height were extended in a column from the top to the bottom of the fluid (see Figure 3) . This `imaginary' cylinder is known as a Taylor column.



When an object moves in a rotating flow, it drags along with it a column of fluid parallel to the rotation axis. This photograph shows the flow when a dyed drop of silicone fluid (radius 2 cm) rises through a large tank of water rotating at 56 rpm