For the same Froude number and depth of submergence beneath a free surface, the wake of a cylinder exhibits two admissible states. The first state involves a jet‐like flow generally attached to the free surface; it gives rise to a large‐amplitude, quasistationary wave. In the second state, the jet is detached from the free‐surface, which exhibits only mild distortion. The critical feature of the transformation between these two states involves the formation of a separated vorticity layer from the free‐surface and its interaction with the vorticity layer from the surface of the cylinder. This transformation can occur spontaneously over a time scale much longer than the Kármán period.
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© 1995 American Institute of Physics.
1995
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