Johng,

I disagree about the term 'bound vortex'. The quote you give is not a definition, and uses the term in exactly the same way that it is used in wing theory, and making the same point. The articles I found, presumably in the same search you did, about swimming and sailing, were clearly written by laymen, who used the term incorrectly. In particular, if one could calculate the circulation around a 'bound vortex', it would allow the direct calculation of the lift. You could not do that with the vortex that exists in the leading edge separation bubble.

I think you may be onto something with the oscillating separation bubbles. It could well be that a separation bubble there would be unstable, and since a bunch of the lift occurs right there, it wouldn't be unreasonable to expect some noticeable change in pitching moments as a result.

banktoturn