Page History

...

Consider a uniform viscous fluid flow past an infinitely cylinder whose diameter is d. The Reynolds numberRe is based on the incident velocity and cylinder diameter.

where is density, is velocity magnitude, is the effective viscosity (laminar plus turbulent). When Re is sufficiently low (less than 47), the flow is symmetric and steady, and a pair vortices are formed behind the cylinder (Fig. 1a). When Re is higher than the critical value, the flow becomes unstable to the perturbations and leads to periodic Karman vortex shedding from the cylinder surface (Fig. 1b). When Re is higher than 180, the flow will become three-dimensional.

...