Lift is normal to the flow, right? (not normal to the wing's chord)
so with an wing inclined to the flow direction (angle of attack), then the lift is acting forward of the normal of the chord,
but not "forward" as in generating thrust.
another day in paradise, or is paradise one day closer ?
I took the question to mean that the summation of all the pressure vectors would point forward of the chord - one might define any arbitrary frame of reference and separate out that vector sum in some other way.
but that's what I meant. Lift is "forward of the normal of the chord" when the wing has incidence, no?
this is why we have to take components of lift to put it into the structural axis of the wing, no?
but this does not create "thrust".
another day in paradise, or is paradise one day closer ?
I made the mistake of posting without really thinking it through. I wasn't really thinking of it in that context but I should have been.
I have a well performing cruising catamaran, the water flow at the stern is flowing up the hull profile and is coming up at 7.5* to the waterline and I have been trying to figure out if I can claim something back by placing a hydrofoil in that angled water flow to produce some meaningful forward thrust.
You would think so but I have done a lot of searching and posting questions on various boating forums, both cruising and racing. There are very few people on those forums who have an understanding of hydrofoils in marine use. I am sure the ones that do are keeping their research to themselves.... ha, racers hey.... but in any event there are next to no boats using foils to assist in drag reduction without flying, it seems to be the domain of the high end boats that fully fly or the dinghy racers who also fly and very little on gaining that few % advantage. I find it hard to believe there isn't something meaningful to be gained in this.
Yes, I was also going to suggest moving this discussion to forum1528, because it seems a hobby question, not work related.
Regardless, it's a displacement hull. Water has to be....displaced.... as the boat moves through the water.
The flow pattern is what it is now because that is quite literally the path of least resistance for that water. Water is lazy like that, it will find the easiest way to get where it needs to be.
Trying to force it to do something else will increase drag.
To decrease drag you need to give it a lower energy option.
I expect enough turbulence is in the mix that surface tension is only a factor for drag rather than keeping the hull in the water.
Coandă may still have something to say - hence the step on float plane floats and hulls to prevent the low pressure at the rear from producing drag at higher speeds. Similar problem though the foil is in the air.
