wind energy site

[hobot]

http://www.du.edu/~jcalvert/tech/fluids/fan.htm

[IntegEner]

The reason for the posting "wind energy site" seems to be support for this studied view by an apparent expert on some aerodynamics. According to my opinion that this subject has become overly characterized as "sacrosanct" in the mind of the public, I view the treatment as wanting to extract gratitude for its ability to bowl everyone over with a rambling sort of expertise. What can be objected to here is that it is intended to be taken by readers pressed for their time after being glanced over as acceptable on its correct sounding conclusions and somewhat dense impenetrability.

It does something of a disservice to the subject in not identifying what might be termed "continuing misleading views and misconceptions" that need identification. No one need fear here that they are being called to account on ideas in their heads that may be wrong.

1. I noticed right away that the mass density of air was taken as somewhat trivial in comparison with that of water at the beginning of it when dealing with wind energy but it wasn't until later on and as an afterthought when dealing with aviation that it was admitted it really is much greater than ordinarily assumed.
   
2. He talks about how Denver would have had little wind energy production from its light winds during some months but never explains how Denver's weather could have changed during those times nor the weather of neighboring states by movement of air masses that extend over large regions.
   
3. There is, of course, an unforgivable absence of the use of energy weighted wind resource averaging in favor of what has always been recorded by the weather people - linear wind velocity averages. Everyone who knows me knows my urgent entreaties to even those in wind energy who should know better to sharpen their math enough to realize the importance of this insight that takes the wind beyond, for example, the comfort wind-chill indexes.
   
4. The idea that aircraft can benefit from propulsion that provides greater mass flow rather than velocity change and hence is physically more efficient, i.e. the use of longer propellers, is provided but lost in the detail of other points being made. The extra large rotors of the Osprey tilt-rotor military aircraft and the well-known extra range of it made available thereby is a concept foreign to most everyone.
   
5. He mentions air viscosity in critical terms but without the necessary elaboration. It is true that the viscosity of air is often taken for granted and to this day wind energy turbine designers have been guilty of not giving this factor its due in describing their products. It is the "kinematic" or specific viscosity of air that is greater than that of water by a large factor - its viscosity as a measured parameter divided by its mass density. Otherwise it is, of course, much less than that of water. This is why, for example, harnessing the power of flowing water with underwater "wind-style" turbines, both the horizontals and verticals, has been found to be so challenging.
   
   

I probably will have more to say about this treatise but am wanting to spend more time on it tomorrow. I have had enough to say today and am pressed for some time now myself.

Anthony Chessick

www.integener.com

[windyknight]

Anthony, I've looked at the link and found it quite informative and balanced and think you're reading more into it than there is! :-)

I'm a great fan of wind and hydro and any concise facts are welcome. If I've time to read 'opinions' I go to the rant section! (hint)

k

[stop4stuff]

Anthony, i get the impression that the article is more of a primer...

Go back to the root page for Dr. Calvert on the University of Denver's severs, the page is part of Dr. Calvert's 'Engineering and Technology' section.

http://www.du.edu - University of Denver site

http://www.du.edu/~jcalvert - Dr.Calvert's pages

http://www.du.edu/~jcalvert/tech/techhom.htm - Enginering and Technology section

loads good info

[IntegEner]

No harm meant or taken. Here is a copy of an e-mail message sent to Dr. Calvert this morning:

"Hello. An item appeared in the postings to the OtherPower.com discussion site on material from a website at the U. of Denver under your name - see http://www.fieldlines.com/story/2005/12/15/6423/8670 . The information provided by me was not intended as criticism and no replies are solicited. In fact, I join with most everyone else in welcoming such commentary on engineering and scientific subjects, something of great value.

"I might make mention of something else. The photo at the bottom of one of the pages shows a sunset scene somewhere in the U.K., all well and good, and a brief search through my own website (www.integener.com) would unearth a mention of an offer to provide sunrise and sunset times for any such location around the world for any recent or upcoming year, all based on the Nautical Almanac of course. The images provided there show how such data can be abbreviated for printing on a postcard or posting on the Internet. Everybody these days being in such as hurry to solve the Global Warming problem, I receive rather limited feedback on this particular item. Anyone wishing to obtain data such as this is welcome to request it.

"Thanks for your time."

Anthony Chessick

www.integener.com

[finnsawyer]

Seeing as how I like to see things presented in a coherent and logical manner rather than blather, I'd just like to point out that there is a fundamental problem with longer propellers.  It's called the sound barrier.  The tip of the propeller can be moving so fast that it reaches the speed of sound causing a shock wave and a great loss of effectiveness.  This has the effect of limiting the speed of propeller driven air planes.  The longer the propeller the lower the top speed.

[ghurd]

And the higher the tip speed, the higher the drag losses.

[IntegEner]

I suppose it is that birds don't know that their long wings also make fine propellers. Critical comments also need to watch the quality of their commentary.

Knucks

www.integener.com

[finnsawyer]

Yes, and birds don't fly all that fast, unless they are acting like dive bombers, in which case their wings are not propellering.  And your point was?  Personally, I am not interested in the aerodynamics of birds.  If you are, I suggest you find another site.  As far as responding to my "critical comments", I would appreciate it if you would stick to the subject and provide a rational, fact filled rebuttal.  As far as quality is concerned, I have not seen one useful piece of information arise from your comments.

[IntegEner]

Sorry that I am such a knucklehead but, after all, what can you expect from someone with a nickname like -

Knucks

www.integener.com

[finnsawyer]

No one is impugning your intelligence.  What I take issue with is your attempt to sell people bad information.  You need to give them something of value in return for their money.  Since yesterday was a slow day, I Googled "Newtonian Principle"- aerodynamics.  It returned your site plus postings on this site.  After reviewing the threads the following occurred to me:  An airplane wing is dragged through the air.  If we eliminate the prop wash and drag it through still air, a pressure wave builds up along the leading edge.  This results in air moving faster over the top surface than over the bottom causing lift.  This is the "classical" view.  My question is this: Since the air is at rest initially, where does the oblique flow of air that you need for your model come from?  The only thing disturbing the air is the wing.  How could this cause a "wind" to appear out of nowhere at exactly the correct angle so it bounces off in the right way to give lift?

[IntegEner]

There is nothing wrong with a little learning as many such as yourself wish to do. My website is a good place to find some answers. If it proves tedious, then I recommend following up on what I have done. Go to this link, the www.wind-toys-online.com">Penney Lynn Wind Toys store ("the wind is our friend"), to see the kites and decorative wind spinners there, very popular even nationwide over the Internet. My 8' tall verticals rotator is located out in front of this store in Littlerock, California, pleasing everyone with its easy-start rotational motion and newfound ability to light a few small lights. The energy is secondary to its attractiveness to homeowners as something that adds to the value of the home. Price: $99.95 + shipping as a kit with a separate order necessary for the 3.5" diameter axial flux generator mounted on it (mine was $30 + shipping from Ed Lenz and others are available). Buy one for yourself and put it together. See how it performs and become part of wind energy. This price is quite low. Take a look at the durable SolarMax cloth toy whirligigs on the website and their quality. Let's get these wind devices moving out to those here who offer us their comments such as yourself and the rest of the public! It is the aviators in these discussions who are so exasperatingly reluctant to see their "coefficients of this and that" and "NACA profiles" so lightly treated. Do you want to see some pics of the IntegEner verticals rotator turning in the wind at its location in front of this retail store?

Anthony "The Knucks" Chessick

www.integener.com

[IntegEner]

I see the link was done wrong. Using cut and paste, it is just www.wind-toys-online.com . Thanks for everyone's patience. Kncks, www.integener.com

[finnsawyer]

Not interested in toys.  End of story.  Have a merry Christmas!