free wake
The following vortex sheet computations were motivated
by the soap-film experiments of
Yves Couder.
A body moving in fluid at uniform speed
creates a free sinusoidal wake
which can be modeled by a suitably perturbed vortex sheet.
In this case,
the wake is symmetric about the horizontal centerline.
The final state resembles a classical Karman vortex street.
If the body oscillates in the
streamwise direction,
the vortices form an array of dipoles which propagate
on one side of the centerline.
With a different streamwise oscillation,
dipoles form and propagate on both sides of the centerline.
References
Y. Couder and C. Basdevant
(1986)
Experimental and numerical study of vortex couples in
two-dimensional flows,
J. Fluid Mech. 173, 225-251
Krasny, R.
(1991)
Vortex sheet computations: roll-up, wakes, separation,
Proc. AMS-SIAM Sem. on ``Vortex Dynamics and
Vortex Methods", C. Anderson & C. Greengard (eds.),
Lects. Appl. Math. 28, 385-402, AMS