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hardingfv32 wrote:

flynfrog wrote:Once again the fences and the slot gap separators in this case are one in the same.

The "duct" on the lotus has nothing to do with the fences on the STR. They are probably taking an area of higher pressure and blowing the wing in one way or another to try to keep a flow attached at a higher AoA or they are trying to shed some drag.

If they are the same, then we have a slot gap separator that improves attachment and/or controls 'cross flow'. Why would Lotus dump flow on a device that promotes attachment or controls cross flow? Why not run a double slot gap separator system and the have a simple main element bottom surface in the center to route flow to.

The question: Why try to integrate the activities of two system that 'seem' to have opposite design goals?

Brian

They are required by rules to have a slot gap separator. My guess is this is causing an issue between the air foils. Extending the separator the back side of the wing may help with the issue they are having. I say guess because we don't know and we don't have enough evidence to make any other assumptions. The lotus device is completely unrelated

flynfrog wrote: The lotus device is completely unrelated

Except for the fact that it is dumping flow in an area that you propose is having trouble dealing with the slot gap separators. Why would they make the situation more complex?

For me, this is not a logical approach.

Brian

hardingfv32 wrote:

flynfrog wrote: The lotus device is completely unrelated

Except for the fact that it is dumping flow in an area that you propose is having trouble dealing with the slot gap separators. Why would they make the situation more complex?

For me, this is not a logical approach.

Brian

Ike I have said a few times earlier we can only tell so much from the floviz. I don't propose to have an answer to what they are trying to do I can only tell you what the flo viz says and that is there there is a large separation behind the that support.

o.k. coming back to the FlowViz interpretation and the effect of the Fences/Slotgap separators a bit, here an related aviation phenomena.



The slotgap separators are similar to what is call "flap tracks" on an aircraft wing.
this may ties in nicely with the McL photo I posted earlier, and I hope sheds some light on some of the patterns seen before.

as a side note:
you see that the AoA is referenced as 4°, even so that the flap angle is actually 35° in this test.
Something Brian should keep in mind. I'm note saying, that he said something wrong, just pointing out that using the term alpha for AoA, while talking about highly cambered wings / or wing-flap combinations (as found in high lift applications) can be misleading at times.
As alpha usually refers to the attitude angle (pitch angle) of the aircraft and not necessarily to the angle of the flow around the wing.
Especially in configurations, which may include variable camber, or as in this example changes in leading edge shape/angle.

At other times, when seeing wings in isolation, the meaning is/can be different.

maybe some will find this helpful