Fluid Vortex Street

Kármán vortex street — alternating vortex shedding from a cylinder
Re = — Vortices shed: 0 Strouhal: ~0.20
1.5
28
0.025
The Kármán vortex street is a repeating pattern of alternating vortices shed by a cylinder in crossflow. At low Reynolds number Re = UD/ν, flow is laminar; above Re≈50, vortices shed alternately from top and bottom, creating the characteristic staggered pattern. The Strouhal number St = fD/U ≈ 0.2 describes the shedding frequency. These vortices cause structural vibration in bridges, chimneys, and submarine cables.