Wind turbine on the front of a car.

[jamesqf]

Originally Posted by aerohead

If you've got some peer-reviewed scientific paper which illustrates how we go from 59.3%,to 100+% efficiency with a turbine electric generator 'd love to see that.

Why do you need to get 100% efficiency? (Let alone more than 100% :-)) You just need to extract more energy than is needed to overcome the extra drag. And as the examples show, it IS possible to do that, just not practical for daily driving. Rather like the solar cars racing across the Australian Outback.

[kach22i]

Originally Posted by jamesqf

Why do you need to get 100% efficiency? (Let alone more than 100% :-)) You just need to extract more energy than is needed to overcome the extra drag. And as the examples show, it IS possible to do that, just not practical for daily driving. Rather like the solar cars racing across the Australian Outback.

Perhaps it would help you to abstract this a bit.

Remember in school all of those math problem solving exercises?

The ones where there was a bunch of stuff on the left side, and bunch of stuff on the right side, and an "equal sign" in the middle.

That equal sign was pretty important wasn't it?

Why was that darn thing there anyway you probably asked yourself over and over and yet nobody could give you a satisfactory answer.

Originally Posted by aerohead

If you've got some peer-reviewed scientific paper which illustrates how we go from 59.3%,to 100+% efficiency with a turbine electric generator 'd love to see that.

What I think aerohead is saying, is that to solve for this problem, both sides of your equation have to equal each other, or complement each other in some way. You cannot have an unequal equation, gotta account for everything or you missed something.

Inequalities ppt revised


Perhaps if someone wrote out an equation showing the energy into the system (power generated), energy out of the system (power used; air drag, rolling resistance) which included the wind turbine as a factor we could all visualize this in a simplified manner and know which category to put things in.

Often defining the problem leads to solving the problem.

In other words, if you cannot define your problem, then you have little hope of solving it.

Identifying the problem is key to it's solution.

You cannot hit what you cannot see, so stop squinting so hard.

[jamesqf]

Originally Posted by kach22i

Perhaps it would help you to abstract this a bit.

Remember in school all of those math problem solving exercises?

BS in Math & Physics, graduate degrees in computer engineering, so yes, I think I have some notion of what an equation is :-)

I think what you're overlooking here is that the (100 - 59.3 = 40.7)% (see, there's an equation for you!) isn't all, or even mostly, going into drag. It's just passing through, uncaptured. Which, when you think of it, is pretty much common sense, since if a turbine captured all the energy from wind, the air would stop moving, and it would be perfectly calm directly behind the turbine.

[aerohead]

Originally Posted by jamesqf

Why do you need to get 100% efficiency? (Let alone more than 100% :-)) You just need to extract more energy than is needed to overcome the extra drag. And as the examples show, it IS possible to do that, just not practical for daily driving. Rather like the solar cars racing across the Australian Outback.

*The wind-powered race cars are traveling at 11.5-mph.
*At this velocity,the car is at sub-critical Reynolds number.
*A 'real' automobile cannot operate at a sub-critical Reynolds number due to the turbulent boundary layer of Earth in which it is traveling.
*'Sail' effects are the reason the wind-powered race cars can move into the wind.
*The turbines on the race cars are gimballed for yawing,to take advantage of relative wind - induced lift/thrust.
*On the front of an automobile,at the forward stagnation point,embedded within the grille area (?),the Prandtl lines of discontinuity in the streamlines would preclude the turbine from relative wind affects,required to produce the thrust present in the race cars.
*We'd be limited to a standard,garden-variety mechanical efficiency for the turbine.
*In traffic,it would be virtually impossible to produce any power,and you'd be relying on battery-alone,which would have to made made up when back underway.
*A conventional belt-driven,shaft-driven,or flywheel-mounted alternator is electrically as efficient as a wind-powered generator,minus drive losses where applicable.
*The mechanical efficiency of a V-belt,cog-belt,serpentine-belt,etc. exceeds the efficiency of a wind turbines ability to harvest energy from the passing air mass.
*On a calm day,the engine in the car would have to produce all the 'wind' for the turbine,and even with a Diesel TDI,we're talking 43% thermal efficiency,to make wind for a turbine which is 59.3% efficient.
*Now we're down to 25.5% efficiency for the electricity,about as efficient as a trash incinerator.
*I'm uncertain as to the minimum velocity of the air column necessary to even begin power generation with a turbine of such small diameter.
*The turbine sections of turbochargers in a 2016 Ford Shelby Super Snake Mustang might be looking at 280-hp worth of hot gases at their inlet.
*The accomplishment of the students,racing into the wind must be taken in view of a very contextual operational environment.

[jamesqf]

Originally Posted by aerohead

The accomplishment of the students,racing into the wind must be taken in view of a very contextual operational environment.

Pretty much true (though some of it is beyond my expertise), but it all seems to add up to just what I said: It is technically possible to do this, just as it is possible to have solar-powered cars. It's just not practical.

PS: FWIW, the current (AFAIK) record speed for a wind-powered car is 126 mph, though with an airfoil "wing", not a turbine. Land record challenge

[kach22i]

Originally Posted by jamesqf

BS in Math & Physics, graduate degrees in computer engineering, so yes, I think I have some notion of what an equation is :-)

I think what you're overlooking here is that the (100 - 59.3 = 40.7)% (see, there's an equation for you!) isn't all, or even mostly, going into drag. It's just passing through, uncaptured. Which, when you think of it, is pretty much common sense, since if a turbine captured all the energy from wind, the air would stop moving, and it would be perfectly calm directly behind the turbine.

Considering the above, me thinks it's time you put all that education to use and show some mad math skills.

Some thing along these lines?

Calculating the Coefficient of Drag - Urbee Example | Sustainability Workshop

The formula would need to be added to and modified a bit, right?

Prove to us that you can make this (compact turbine generator) mathematically work.

Maybe this is why such things are called "proofs".

[jamesqf]

Originally Posted by kach22i

Prove to us that you can make this (compact turbine generator) mathematically work.

You know, you have things exactly backwards. There are, in the posted links, working physical examples. (Although, as I keep saying, not in practical daily-driver conditions.) So if your equations say they can't work, then either your theory or your math is wrong. "Eppur si muove."

[aerohead]

Originally Posted by jamesqf

Pretty much true (though some of it is beyond my expertise), but it all seems to add up to just what I said: It is technically possible to do this, just as it is possible to have solar-powered cars. It's just not practical.

PS: FWIW, the current (AFAIK) record speed for a wind-powered car is 126 mph, though with an airfoil "wing", not a turbine. Land record challenge

Brent Singleton,of Ogden,Utah has a 'Quadbrid' Ford Escort (hybrid,solar,and wind-powered) that he pulls a hybrid LSR racer to Bonneville with.
He uses two wind turbines to help charge with.They're not mounted on the vehicle,and they're not duct-augmented,but he is harvesting power with as modern a technology wind plant as is commercially available and will fit in a car.
He's been at it since age 14,racing for public awareness:International Alternative Fuels Racing Association,International Alternative Fuels Racing Association.
Brent's is enjoying some of the fruit the race teams in the Netherlands have been sampling.

[gone-ot]

Think about this: a "feathered" propeller doesn't rotate, but with added pitch, that same propeller then "wind-mills" and starts its engine...non-aero AIR flow has power. Thus, hanging a wind-powered generator is little more than an "useful" aero-drag device, an electricity producing "brick".

[Hersbird]

Originally Posted by jamesqf

You know, you have things exactly backwards. There are, in the posted links, working physical examples. (Although, as I keep saying, not in practical daily-driver conditions.) So if your equations say they can't work, then either your theory or your math is wrong. "Eppur si muove."

I agree! I wonder if they read this link. I know it is long but it shows they proved the physics 99% of people thought was impossible was in fact possible.
One Man's Quest to Outrace Wind | WIRED
In a 15 mph wind he went 46 mph directly downwind! It seems like a magical energy machine but read the whole article and watch that CGI video in the middle. It really blew my mind.