Fig 46. Circular cylinder at R=41

Experiment

Simulation

“This is the approximate upper limit for steady flow. Far downstream the wake has already begun to oscillate sinusoidally. Tiny irregular gathers are appearing on the boundary of the recirculating region, but dying out as they reach its downstream end.” Photograph by Sadathoshi Taneda

Flow separation #

This post is part of a series on flow separation, studied for the case of flow past a circular cylinder at different Reynolds numbers. The current figure, roughly represents the upper limit for steady flow. When increasing the Reynolds number, the flow will start to oscillate and develop into a periodic state. More information on such a “von Kármán vortex street” can be found in the web post from Figure 94.

The main theory and simulation and visualization set-up are discussed in the web post from Figure 42. The full series is:

• Figure 24: Circular cylinder at R=1.54.
• Figure 40: Circular cylinder at R=9.6.
• Figure 41: Circular cylinder at R=13.1.
• Figure 42: Circular cylinder at R=26.
• Figure 45: Circular cylinder at R=28.4.
• Figure 46: Circular cylinder at R=41.
• Figure 96: Kármán vortex street behind a circular cylinder at R=105.
• Figure 94: Kármán vortex street behind a circular cylinder at R=140.

An overview of these posts can be viewed here: