Foil Kayaks exist
IF you paddle very hard and fast, it is possible
to use a "foil" to gain lift ; in a kayak
http://www.youtube.com/watch?v=S5Nb3iGdTEM
http://www.youtube.com/watch?v=OuvtFX_iikc
Getting a kayak to "slip" forward in current;
is yet quite another thing altogether.
Hydrofoil
I think I should add some info.
It’s hydrofoil (http://en.wikipedia.org/wiki/Hydrofoil) they are designed to lift the craft vertically and greatly reducing the “drag”
Turbulence
On my first video I try to steer the “boat” to the middle of the steam to avoid turbulence (or whatever you call); in my second video since I have 1 hand, jumping up& down . . . I was unable to do so. And the purpose of this video to show my setup + the environment how the first was made up.
Phi.
Yes
They travel at close to 3x the wind speed, e.g., faster than the wind.
If you look at the video, they start with the wind in their back. The wind is pushing them up to speed, then they begin to move faster than the wind and now the wind blows against them. Say the wind is 10mph, they are traveling at 30 mph in the same direction. So their relative speed compared to the wind is 20mph faster than the wind, and in the same direction as the wind.
No magic here -;) Read-up on it and you'll find out how it's done. Read about "apparent" wind. Read about foils. You'll find enough information about sailing faster than the wind - this is a well established fact. Fast sail boats can travel faster than the wind speed. So can land-sailing vehicles. The difference here is that the wind's energy is transferred to the ground via the wheels of the vehicle and a transmission drive, which allows the turbine powered vehicle to travel downwind faster than the wind. A regular sail boat (with a sail and no transmission to a propeller under water) cannot travel faster than the wind downwind but can do so at an angle to the wind.
A turbine powered sail boat can travel in *any* direction, including directly against the wind. Look-up some other videos if you like. There is a guy actually sailing one of these to demonstrate how he can go in any direction he wants...
The same principles apply with the other link I posted of the little boat that can travel directly against the wind with no motor or current pushing it - using only the wind's power.
Again, to these types of speeds the term "apparent wind" is the key to understanding how it works.
And YES, your theory of floating upriver *is* flawed. You can't do that using only the power of the current. Not the way you are trying to do it.
OK. Let me be clear. You [probably] *can* do it but *not the way you are saying*. Now, that would be a worthy project to try, unless someone else has already done that... Looking at the above, can you guess how to do it? Well, here's the answer: you can travel against the current using only the current's power and no eddies and no back currents. Create a transmission that transfers the energy from the water over to a wheel that rolls on a trail along the river, thus giving traction to the boat so it does not slip backwards and can travel forward. This would be the equivalent of the turbine-powered sail boats that can travel against the wind. Now, if you like, you can also travel downriver faster than the flow by using the same principle as the downwind traveling turbine powered vehicle in the video... I suppose, the principle here would be called "apparent current" to parallel the "apparent wind" term for the air...
Or perhaps, stretch a wire (like a zip line) above the river and use the river current to power a turbine to allow your boat to travel up or down or sideways the river current with the wheel hooked-up to that zip line... That would be a nice way to power a ferry across the river with no engine to use fuel. Most such ferries already have a line to which they clip to stay straight across the current of the river. With a current driven turbine instead of an engine or a person pulling the rope, you can move back and forth across the river all day and not use one bit of energy for that...
This is the same idea as the kite: only instead of the string holding the kite, these vehicles that use turbines hold on against the ground through their wheels. Or use a propeller under water to provide a support point against the wind that powers them. In your case, to use the current, you need a support point (e.g., the string of the kite - in that case you can use a string/zip line or a wheel on the ground along the river...). Why is your experiment not working - because your foil has no support point: it is a lever without support. In contrast, the videos I showed you have a support point for their lever system - the ground or the propeller under water; regular sail boats too have a support point - their hulls and the rudder/thingy under them pushing sideways against the water (and as they pick-up speed, these underwater areas act as foils, if they are well designed)
Even more. . . .
When applying "apparent wind" . . . . Down wind???? (in relate to the motion vector)
When moving down wind.
At 0x speed ====> apparent wind = 1x
at 1x down wind ====> apparent wind = 0x
at 2x down wind ====> apparent wind = -1x
at 3x down wind ====>apparent wind = -2x
at 4x down wind ====>apparent wind = -3x
When moving up wind.
At 0x speed ====> apparent wind = 1x
at 1x up wind ====> apparent wind = 2x
at 2x up wind ====> apparent wind = 3x
so on . .
No
Your numbers describe the relative speed of the wind compared to the boat.
However, "apparent wind" is not necessarily the same thing. It is not as simple as the relative speed of the wind compared to the speed of the boat. Read here: http://en.wikipedia.org/wiki/Apparent_wind
In sailing, the apparent wind is the actual flow of air acting upon a sail, which is not necessarily the same as the speed of the boat moving relative to the wind's speed.
Let's look at a specific example. A sail boat boat is moving at 10 miles per hour (mph) and the "true wind" is also 10 mph blowing at 90 degrees to the direction of boat travel. In this case the "apparent wind" for a person sitting at the boat will still be 10mph. But the "apparent wind" at the front of the sail will be more than 10mph, e.g., faster than the speed of the "true wind" or the boat's speed, which we said are the same in this particular example.
To understand the above, keep in mind the sail (or the turbine wing) is a foil. And the way air flows around foils is the key to understand why it is possible to travel faster than the wind. The air speeds-up on the convex side of the foil - think of airplane wings as they generate "lift" due to that difference in speed of the air traveling on both sides of the wing. Same principle here with sailing faster than the wind: the foil creates "lift".
From Wiki . . . .
"Now suppose there is a 5 mph wind coming directly from the north. If you pedal at 10 mph due north, you will feel an apparent wind of 15 mph from the north. But if you pedal 10 mph due south, you will feel an apparent wind of 5 mph from the south."
Moving down wind = "due south"
at 10mph ===>feel like 5Mph from south = (-1X) (against the actual wind direction)
More elaborate :
At 5mph ==> feel like no wind.
At 15mph ==> feel like 10mph from SOUTH. so on . . .
If the guy "due south": At what speed does he feel like 30mph (3x) from NORTH ? ? ? ?
to go against the current
I have a you tube video on “kayaking up thru rapids”. It isa big part of my. Less hassle to do a loop and much more exciting. The bottom of the riverbed is not smooth. Water goes down but eddies force some of the water to go back up. This si why niagara falls is being undercut and is moving upstream. You can surf below a rock as most water is going downstream but some is taking you back up. The toughest to paddle upstream is over a flat riverbottom. Too high a coefficent of friction. Not enough waves to bounce you up.
Rocky riverbottom will cause the bottom of the boat to ride over the waves upstream almost like rolling a log upstream. Less drag as boat is up out of the water
Just tested different configuration
I just tested different configuration (not exactly as you suggested). Where (1) the hose points to the left wall to eliminate the jet stream affect and (2) start the model from the far right - 6', 7' from the left wall.
They are all moving R->L as usual but apparently at slower speed (but not too slow) as expected due to the absence of the added speed from the jet stream.
No foil to propel forward
I highly doubt any foil shape in the water
will provide enough force to propel “man and boat”
-forward- against the moving current.
A “new” hull shape…unlikely
Some of us paddle “swede” shape hulls -Epic Endurance 18.
Others paddle surf skis and similar built fast kayaks.
The hull shape determines how far back from the bow
the region of laminar flow goes,
before turbulence sets in,
and starts stealing energy to create eddies.
Finding a new shape to “propel” us forward is unlikely.
yep
I think I saw some grass clippings and/or some such similar debris in the water also “propelling itself” upstream in eddies and return flow.
Several things
You seem to be missing the point that the wind that propels the boat matters at the sail not at the guy who’s in the boat.
North wind at 5mph, you travel south. To move at 3x the wind speed, you need to be traveling at 15mph in the direction of the wind. The guy in the boat will feel a 10mph wind in his face. This is simple enough.
However, I think you do not understand how it is possible to move faster than the wind downwind. To understand this you need to look closely at what the air is doing around the moving blades of the turbine. At the trubine blade the local velocity of the air flowing around the airfoil of the blade is much higher than 15mph! This is the “apparent wind” that matters, not the wind in the sailor’s hair.
If you do not understand this or why it is possible, do some reading on the subjest of sailing faster than the wind. Not necessarily directly up or downwind, which introduces yet another dimension to understand. First figure out how a regular sailboat or land sail can move faster than the wind at a “normal” angle to the wind. There is a lot written on the subject so no need to repeat here. Then understand how the little catamaran model in my video works and is able to sail directly against the wind or how the downwind faster than the wind is possible in that other video.
a simple answer
technicalities aside, one great thing i descovered for paddling up twisty channels in current is that with 2 of my boats(Flashfire,Echo)I can paddly with little steering correction when going upstream and do most of my steering by healing(carving) my boat. this enables my to concentrate my limited power to fighting the current.
turtle
A similar trick for going upstream:
There’s always some degree of eddying flow on the river’s curves. There may not be a reverse flow, and even if there is, your boat may not pass through that “true” eddy zone, but there will at least be a gradation of progressively slower current as one moves closer to the inside of the bend. That means that when going upstream on curves the water will normally be streaming past the boat noticeably faster on the side toward the outside of the bend than on the side facing the inside. By paddling on the side toward the outside of the bend you can at least reduce, and usually eliminate, the need for correction strokes since the boat already “wants” to turn toward the zone of water that’s passing the hull more quickly (the boat’s naturally turning toward the outside bank is opposite of what happens when going downstream, but the hydraulic principle as experienced by the boat is exactly the same). You can save a lot of energy that way paddling on the “good side” around the curves, especially if you are trying to cover a lot of distance in a hurry.
we use mind control …
… to make our canoe go where we want it to .
Works just as well going up river but one needs to focus the mind more in that direction .
an experiment to try…
instead of a hose have a larger pool of water spilling into the trough such that the spillage is near the width of the trough. THEN have the bottom of the trough flow as a waterfall into another pool. This should mostly avoid the eddies that can happen with a narrow stream like a hose or from any rebound from the bottom of the trough. Since there was some small bits of debris in the video also going upstream it's clear there was some eddy like disturbance and this change in the experiment may remove most such eddies.
if you try this and video be sure to pan back far enough to clearly see the entire experiment layout.
We did it too!
The same things happen.
Thanks
video?
of that showing total flow from source to drain? Seeing will help all to appreciate any lack of back flow (eddies and such). I only watched the first video you linked to which did show a back flow as evidenced by debris movement.
okay saw second vid you posted…
I see something near hose that I assume is to distribute the water flow better but I didn't seen the drain part. Anyway in that second video you put some dye in the water and some of that dye goes upstream suggesting there is still some upstream current similar to an eddy.
You need to replace the hose completely with some wide mouth 'waterfall". Is the bottom of the trough closed or wide open and flowing (another waterfall) into some lower pool/ground? If the bottom of the trough is closed you will get up currents. If the hose water isn't very evenly distributed you will likely also get some up current when the water bounces off of the sides of the trough.