Schmidt Wave Propellor

[clmanges]

I'm starting this thread as an exploration of drive systems based on winglike foils that move in relation to each other. I was going to take up this question in my other thread about a drive system for my rowboat (see thread "I'm new here" under Boat Design), but thought that this topic deserves its own thread.

The basis for my query here derives from papers by Kevin D. Jones:

http://aa.nps.edu/~jones/

and specifically,

http://aa.nps.edu/~jones/research/un...methods/anim3/

You'll find elsewhere that research has been done on two-foil systems with a pure plunging motion of one foil (as compared to rotary), with a downstream stationary foil. And that's the departure point for this thread.

In the Schmidt system, the downstream foil is "passive" because it doesn't create its own flow pattern. (I know that "passive" is not exactly a correct term here, because the foil does produce thrust -- I think it's safe to call it "quasi-passive" for now; better definitions are always welcome.)

Now, what if both foils move? I can think of a number of possible configurations, but for now I'd like to look at pure plunging motion.
Let's start with the case of opposed plunging motion: one foil is going up while the other goes down; their motion is 180 degrees out of phase.

What kind of interaction results from this? Will it always produce a thrust pattern (a reverse Karman street)?

What think ye?

Curtis