lördagen den 29:e september 2012

Why My Book is Banned by KTH


My ebook BodyandSoul Mathematical Simulation Technology (MST) is banned by KTH: No link to the book is allowed on any website controled by KTH.

If you want to know why KTH exercises this oppression of free speech, the most holy principle of both science and democracy, you will find the answer in the following TED talk by Conrad Wolfram:
What Wolfram says is precisely what MST says: 
  • We've got a real problem with math education today.
  • I believe that computers correctly used is the silver bullet that can make math education work.
  • Computer-based math: Critical reform.
  • The country that does it first will leap-frog others.
  • This is not an incremental sort of change.
  • I want to see a completely renewed changed math curriculum built form the ground up based on computers...
  • I am not even sure we should brand the subject as math.
  • What I am sure is that it is the main-stream subject of the future.
This is revolutionary and this is why MST is being banned by KTH. See also computerbasedmath.org.

fredagen den 28:e september 2012

Why Circulation Theory of Lift is Unphysical

The Kutta-Zhukobsky circulation theory of lift is considered to explain how a wing generates lift. The usual text-book presentation of circulation theory starts out with the so called Magnus effect of a circular cylinder which is moving perpendicular to its axis (from left to right) while rotating (clockwise) around its axis, described by the following picture supposedly describing a section of the flow (right) resulting from potential flow (left) augmented by circulating flow (middle):



The idea is that the rotation of the cylinder somehow by viscosity generates the circulating flow, which redirects both the incoming and outgoing flow and thus generates an upward reaction force on the cylinder as a lift force.

But the flow pattern in the right picture is not what observed. It is unphysical because
  1. It is symmetric in the flow direction. Reversing the flow will give the same picture. The real flow is not symmetric: the flow attachment and flow separation are different.
  2. The incoming attaching flow in the right picture has a different direction than that of the left picture. It is inconceivable that the mere rotation of the cylinder can cause such a major change of the incoming flow.
The real flow simulated by solving the Navier-Stokes equations for a non-rotating sphere (left) and rotating sphere (right) is shown below, in both cases with incoming horizontal flow from left to right:












We see that the flow is unsymmetric in the flow direction both with and without rotation. We see that with rotation the separation is unsymmetric in the vertical direction, which is the true cause of the lift, not large scale circulation with symmetric attachment and separation, as in the unphysical right picture above.



It is instructive to compare with the following picture on Wikipedia which also shows an unsymmetric flow (now from right to left) with different separation and attachment:

See also Why a Topspin Tennis Ball Curves Down.









After this preparation circulation theory of lift of a wing is then typically pictured as follows suggesting the presence of a large scale circulation generating lift:


But this is again a picture of an unphysical mechanism which does not describe reality. The true mechanism is revealed in New Theory of Flight and as above results from different flow attachment and separation.

Watch the incorrect circulation theory:

onsdagen den 26:e september 2012

Incorrect Fundamentals of Aviation


The book Fundamentals of Aviation and Space Technology, published by University of Illinois/Urbana in 1962, is presented as follows:
  • The reception accorded the first edition of this book under its present title was very gratifying. It appealed especially to teachers and students, as well as to the  air transportation industry for orientation courses. 
  • The continued success of the book has again exhausted the supply, and a new printing is necessary only two years after the previous revision.
As an apparently very successful example of a university level educational text, let us check how the Theory of Flight is presented in Chapter 3. It starts out
  • Whenever, in casual conversation, a group of people start to discuss airplanes, someone is almost certain to exclaim, "Why, some of those airplanes weigh tons. I don't see how they stay in the air." Very few people understand the forces that control an airplane in flight. 
  • For many years engineers have studied the motion of air over airplane parts in order to learn how a change in the shape of the part affects the force created on it by the moving air. Although a large amount of information is presently available on this subject, the desire to make airplanes go higher, faster, farther, and carry greater loads requires continuous research.
Then follows the "equal transit time" theory = Incorrect theory #1 identified by NASA:
  • If we move the wing through the air at a relatively high speed with the rounded or leading edge forward, the following things happen: The blunt and thick leading edge pushes the air out of the way. Part of this displaced air flows rapidly (the speed is important) over the wing and part of it flows under the wing. The layers of air, after going over and under the wing, join again behind the trailing edge. 
  • The important thing to remember is that due to the curved upper surface the air that flowed over the wing had to go farther than the air that went under the wing. 
  • Consequently, air that flowed over the wing had to travel faster than the air that went under the more or less flat bottom surface. 
  • The air which had to travel farther across the top of the wing is stretched out and becomes thinner, creating a reduced pressure on the upper surface. 
  • The air traveling along the bottom of the airfoil is slightly compressed, and consequently develops increased pressure. 
  • The difference in pressure between the air on the upper and lower surfaces of the wing, when exerted on the entire wing area, produces lift. 
But this was 50 years ago, you may say: It cannot be true that books of today continue to teach theories of flight which are known to be incorrect.

But then you are wrong! There is no current text-book which teaches a correct theory of flight. It is now time  to rewrite text-books to teach the New Theory of Flight.

PS Checking pageview statistics of this blog I see that the interest in understanding what keeps airplanes in the air appears to be close to nil. Can it be that 100 years of incorrect theories has ruined the subject? If so, it is now high time for revival of the keen interest 100 years ago from the pioneers of aviation.

Letter to NASA Glenn Research Center

Thomas Benson
Glenn Research Center

Hi again Tom:

I hope you are willing to continue the interview from 2009. Since then we have completed our New Theory of Flight which is presented on the web site The Secret of Flight.

The New Theory is now under review by AIAA with communication recorded here.

In your Beginners Guide to Aeronautics you still write:
  • The real details of how an object generates lift are very complex and do not lend themselves to simplification. 
  • To truly understand the details of the generation of lift, one has to have a good working knowledge of the Euler Equations.
My questions:

1. Do you have the required "working knowledge of the Euler Equations" and do you "truly understand the details of the generation of lift"?

2. If not, can you direct me to a person at NASA or outside with this knowledge?

3. Since 2009 you have added circulation theory, with starting vortex et cet, to the Beginners Guide.
Is this supposed to be the knowledge asked for in 1?

I hope you will answer my questions, and also take up the New Theory of Flight to discussion/evaluation at NASA.

We have massive evidence from mathematics, computation and experiment supporting the New Theory and we are confident that we have something new of genuine interest to NASA.

Best regards,

Claes

tisdagen den 25:e september 2012

NASA: What Keeps Planes in the Air?

                                             Dad, what keeps the airplane in the air?

To check if someone understands a physical phenomenon it is often instructive to study how it is presented to young innocent minds. As an example, let us see how NASA Glenn Research Center in its Beginners Guide to Aeronautics, explains how an airplane is kept in the air by an upward lift force generated by the wings balancing gravitation:
  • How is lift generated? 
  • There are many explanations for the generation of lift found in encyclopedias, in basic physics textbooks, and on Web sites. 
  • Unfortunately, many of the explanations are misleading and incorrect. 
  • Theories on the generation of lift have become a source of great controversy and a topic for heated arguments for many years.
  • The proponents of the arguments usually fall into two camps: (1) those who support the "Bernoulli" position that lift is generated by a pressure difference across the wing, and (2) those who support the "Newton" position that lift is the reaction force on a body caused by deflecting a flow of gas.
  • Which camp is correct? How is lift generated?
After this challenging start NASA disappoints the curious young mind by:
  • The real details of how an object generates lift are very complex and do not lend themselves to simplification.  
  • To truly understand the details of the generation of lift, one has to have a good working knowledge of the Euler Equations.
NASA thus has no explanation of lift to offer, only a mathematical Euler Equation mystification, and so in a desperate move to maintain scientific authority and credibility resorts to presenting, instead of any correct theory, three incorrect theories: "equal transit time", "Venturi" and "skipping stone".

But if NASA would learn about the New Theory of Flight then NASA would be able to fill its mission to reach young minds with essential science, instead of as now delivering only mystical or incorrect science.

I have tried before to get the attention of NASA (see Interview with Glenn Research Center from  2009) and will now make a new try and report...

PS In a last attempt to save face NASA throws in circulation theory:
  • From a Newtonian perspective, lift is generated by turning a flow of air. 
  • The flow turning that occurs in the creation of lift also creates bound vorticity within the airfoil.
  • The existence of the bound vortex (or vortices) within the airfoil created an important theoretical problem when it was first proposed.
  • With a bound vortex within the object, there would then have to be another vortex of opposite strength present within the flow domain.
  • It took some very careful experimental work by Ludwig Prandtl to actually "catch" the other vortex on film (the so-called starting vortex)
Computer drawing of an airfoil showing the bound vortex
 and the shed vortex.
The New Theory of Flight shows that this 2d picture does not describe actual real 3d physics, only fictional physics which only Prandtl could "catch" in his mind, as a mystery to generations of aerodynamicists flocking at NASA.


måndagen den 24:e september 2012

Direct Simulation of Flight Stability

The New Theory of Flight based on computational solution of the Navier-Stokes equations with slip boundary condition allows direct simulation of dynamic flight stability under the action of aileron, rudder and elevator using the Fluid-Structure-Interaction code Unicorn/FEniCS. This is a new capability which opens many possibilities of new design and control.



AIAA says no-thanks to this capability when rejecting the New Theory of Flight. It is not so clever. Compare Flapping Bird.

New Theory of Flight vs Observation


This picture from the Dryden Water Tunnel shows the 3d rotational separation at the trailing edge of the wing, which is a central aspect of the New Theory of Flight, as illustrated in the following generic image:


We see the dye injected on top of the wing follow a streamline along the surface without rotation until the trailing edge where counter-rotating rolls are formed as in the following Navier-Stokes simulation of the flow around a circular cylinder displaying 3d rotational separation:



Aerodynamics Expertise Without Knowledge


Aerospaceweb.org is
  • a non-profit site operated by engineers and scientists in the aerospace field. The goal of this site is to provide educational information on a variety of subjects ranging from aviation to space travel to aerospace technology. Our primary areas of expertise include aerodynamics, propulsion systems, vehicle design, engineering career information, and aerospace history. Learn more about these and other topics by visiting the following sections of our site.
Under Aerodynamics Questions we read as an answer to the question How Does a Wing Work?:
  • So the reader may be asking which of these theories (Bernoulli, Newton, Circulation) is correct
  • In truth, each is valid in some respect and useful for certain applications, but the ultimate question is which is the most fundamental explanation. 
  • Mathematicians would surely prefer the circulation theory, which is certainly a very elegant approach firmly based on mathematical principles, but it fails to explain what force of nature creates circulation or lift. 
  • Many would argue that the Newtonian explanation is most fundamental since it is "derived" from Newtonian laws of motion. While this is true to some degree, the theory lacks an explanation as to why an airfoil deflects the flow downward in the first place. Even accepting this principle, the idea that an airfoil deflects the flow and therefore experiences lift also fails to capture the fundamental tools of nature (pressure and friction) that create and exert that force on the body.
  • Proponents of this explanation generally deride the Bernoulli theory because it relies on less fundamental concepts, like the Bernoulli and Continuity equations. There is some truth to this complaint, and the theory may be more difficult for the novice to understand as a result.
  • However, both equations are derived from Newtonian physics, and I would argue from more fundamental and more mathematically sound premises than the Newtonian theory. 
  • In the end, I leave it up to the reader to decide.
We see here the collected expertise of aerodynamics being unable to explain anything of value about the generation of lift of a wing, simply giving up and passing the question of How Does a Wing Work  over to the reader. 

But there is a New Theory of Flight giving a true scientific explanation different from the above trivial no-explanations.

Pilots Fooled by Federal Aviation Administration

Let us now check out how the generation of lift of a wing is presented in Pilots Handbook of Aeronautical Knowledge by Federal Aviation Adminstration. We read in Chapter 3 Principles of Flight:
  • The formulation of lift has historically been the adaptation over the past few centuries of basic physical laws. These laws, although seemingly applicable to all aspects of lift, do not answer how lift is formulated. In fact, one must consider the many airfoils that are symmetrical, yet produce significant lift.
This is not a very promising start. The next step is a digression into the Magnus effect of a rotating cylinder:
  • In 1852, the German physicist and chemist, Heinrich Gustav Magnus (1802–1870), made experimental studies of the aerodynamic forces on spinning spheres and cylinders. (The effect had already been mentioned by Newton in 1672, apparently in regard to spheres or tennis balls). These experiments led to the discovery of the Magnus Effect, which helps explain the theory of lift.
  • To summarize the Magnus effect, an airfoil with a positive AOA develops air circulation about the upper surface of the wing. Its sharp trailing edge forces the rear stagnation point to be aft of the trailing edge, while the front stagnation point falls below the leading edge. [Figure 3-4]

We see here an attempt to explain the Kutta-Zhukovsky circulation theory, which is unphysical by asking the incoming flow to change direction. This is sensed by FAA feeling that prospective pilot will not be convinced, and so seeks to enhance the message by: 
  • A half-century after Newton formulated his laws, Daniel Bernoulli, a Swiss mathematician, explained how the pressure of a moving fluid (liquid or gas) varies with its speed of motion. Bernoulli’s Principle states that as the velocity of a moving fluid (liquid or gas) increases, the pressure within the fluid decreases. This principle explains what happens to air passing over the curved top of the airplane wing. 
This time it is not circulation but instead Bernoulli with lower pressure above supported by a picture illustrating the Venturi effect:

FAA thus hints at the "Venturi" effect, which however is identified by NASA as Incorrect Lift Theory #3.

The discussion is then rounded off by:
  • Since air is recognized as a body and it is accepted that it must follow the above laws, one can begin to see how and why an airplane wing develops lift. As the wing moves through the air, the flow of air across the curved top surface increases in velocity creating a low-pressure area. 
  • Although Newton, Magnus, Bernoulli, and hundreds of other early scientists who studied the physical laws of the universe did not have the sophisticated laboratories available today, they provided great insight to the contemporary viewpoint of how lift is created. 
We see again how a governmental agency struggles with the sad fact that there is no convincing theory of lift offered by aerodynamicists to be taught to pilots. 

The New Theory of Flight presented on The Secret of Flight is the first scientific explanation of the generation of lift of a wing, and as such it both describes real physics and is possible to understand, by both prospective pilots and air passengers.

söndagen den 23:e september 2012

Flight Theory in NSF GK12 Aerodynamics Contradicted by NASA

The NSF GK-12 Wind Energy and Aerospace Workshop 2009 teaches young minds about Fundamentals of Flight, Stability and Control in the following pictures:







We see here the "Venturi" theory which is described by NASA as Incorrect Theory #3. This is yet another example of a science of aerodynamics in crisis with contradicting messages sent by different parts of the science administration here in the form of NSF and NASA.

Unphysical AIAA Lift Theory


















Performance, Stability, Dynamics and Control by B. N. Pamadi in AIAA Education Series, describes the generation of lift of an airfoil as follows (with illustrations above):
  • The lifting line theory will be used to obtain expressions for the lift-curve slope.
  • In lifting line theory the wing is modeled as a horse-shoe vortex formed by a bound vortex, trailing vortices from the wing tips completed by a so-called starting vortex.
  • The bound vortex induces an upwash in from of the wing and a downwash behind. The trailing vortices induce downwash everywhere ... negligible in the vicinity of the wing.
  • To understand how a starting vortex can be a physical reality....
This is Prandtl's lifting line theory. The basic idea is that the bound vortex generates upwash in front and downwash behind and thus generates lift.

As indicated by the phrase "to obtain expressions" (for the lift-curce slope), lifting line theory is on one hand not really supposed to describe actual aerodynamics but only give a way of computing the one number of the lift-curve slope, and on the other hand it is described in suggestive pictures as if being real in some sense, although the action of the starting vortex is surrounded by mystery. The presentation is thus ambigious.

The truth is that lifting line theory does not describe actual physics: The upwash in front of the wing is not seen in real flow, nor in Navier-Stokes simulations, and in fact not in the top left picture either. What is seen is downwash at the trailing edge as a result of 3d rotational separation as described in the New Theory of Flight.

The New Theory is in the words of AIAA editor Greg Blaisdell, when rejecting it for publication in AIAA Journal, described as follows:
  • Your paper is unusual in that it challenges our existing understanding of aerodynamics.
Yes, it does, and shows that existing understanding is incomplete. To reject work increasing understanding is not beneficial to the science of aerodynamics and to engineers designing airplanes.


lördagen den 22:e september 2012

AIAA Lift Theory Contradicted by NASA










The generation of lift of an airfoil is described in Introduction to Aeronautics: A Design Perspective in AIAA Education Series with support of the above pictures, as follows:
  • As the flow moves downstream, the orientation of the airfoil causes more of an obstruction to the flow above it than it does to the flow below it. This obstruction to the flow causes the stream tube above the airfoil to be constricted. 


We see that AIAA and NASA present contradictory information about the most central problem of aeronautics: generation of lift by a wing. Notice also the unphysical high pressure at the trailing edge on the upper right picture.

This is yet another illustration of the complete collapse of aeronautics education fostered by AIAA, making it possible to reject the New Theory of Flight without real scientific evaluation.

fredagen den 21:e september 2012

Aircraft Design Engineers Fooled by AIAA



Let us continue our study how AIAA expresses its world-leading expertise in the book Aircraft Design: A Conceptual Approach, by D. Raymer, 1992, published in the AIAA Education Series described as "creating a comprehensive library of the established practices in aerospace design" with the following conclusion of the Foreword: "For many years Aircraft Design will be a valuable text book for all who struggle with the fundamentals and intricacies of aircraft design".  We read on p 35 under Airfoil Lift and Drag: 
  • An airfoil generates lift by changing the velocity of the air passing over and under itself. The airfoil angle of attack and/or camber causes the air over the top of the wing to travel faster than the air beneath the wing.
  • It can be seen that the effect of the airfoil is to introduce a change in airflow, which seems to circulate around the airfoil...
  • This "circulation" is the theoretical basis for the classical calculation of lift and drag-due-to-lift The the greater the circulation the greater the lift. 
  • Odd as it sounds, an airfoil in two-dimensional flow does not experience any drag due to the creation of lift. 
  • The figure below shows typical pressure distributions for the upper and lower surfaces of a lifting airfoil at subsonic speeds. Note that the upper surface of the wing contributes about two-thirds of the total lift. 

AIAA thus sells the 2d Kutta-Zhukovsky circulation theory of lift. AIAA claims that the theory offers a way to calculate lift and drag, but then directly admits that the drag comes out to be zero, which is described as "odd".

But AIAA does not admit that the pressure distribution in the presented figure with its high pressure at the trailing edge suggested by the theory, is not what is observed in reality. 

AIAA is thus fooling aircraft design engineers into relying on an unphysical theory which does not describe reality. AIAA continues along the same track by rejecting the New Theory of Flight without proper evaluation, which is also "odd".

AIAA further ruins the hope of any prospective CFD-user during any foreseeable future:
  • No current codes actually attempt to solve the true full Navier-Stokes equations due to the difficulty of mathematical analyzing turbulence. Turbulence occurs at the molecular level, which would probably require gridding with billions of molecular sized grids. 
  • CFD does not replace the wind tunnel. In fact , it really doesn't even reduce the number of wind-tunnel test hours.
But if this was true in 1992, it is not true any more in 2012: The computations behind the New Theory of Flight shows that it is indeed possible to solve the full 3d Navier-Stokes and thereby compute lift, drag and pressure distribution for a full aircraft using affordable millions of mesh points, thus basically eliminating the need of a wind tunnel. This possibility is today rejected by AIAA without evaluation, which is another way of fooling aircraft design engineers.

Von Karman on Incorrect KZ-theory of Lift
















The above pictures from von Karman's Aerodynamics (1954) compares the lift coefficient for different angles of attack (left) and pressure distribution around a NACA 4412 airfoil, between Kutta-Zhukovsky circulation theory of lift and experimental values.

We see that the theoretical lift coefficient is too big and does not include the drop at stall at 16 degrees, and that the high pressure at the trailing edge from theory is not observed in experiments.

Von Karmann comments on p 46:
  • The pictures show that the usefulness of the theory is restricted to a limited range of angles of attack, comprising relatively small angles, positive and negative. Beyond this range the measured values falls far below the values predicted by the theory.
This comment alone would have been sufficient to discard KZ-theory as unphysical (and thus dangerous to use), if there had only been a better theory around. But it was not and so the incorrect KZ-theory has survived into our days as the text-book theory of lift. 

With the advent of the New Theory of Flight as the first the physically correct theory predicting both lift and pressure distribution in close correspondence to observation for all angles of attack including stall and beyond, the KZ-theory can now finally be put into the wardrobe of incorrect physical theories along with flogiston theory. It will take some time before this is realized and acknowledged by AIAA: The World's Forum for Aerospace Leadership, but it will come.



torsdagen den 20:e september 2012

Ahlborn: Early Critic of Prandtl


Friedrich Ahlborn (1858-1937), a today forgotten pioneer of fluid dynamics, performed and photographed experiments in Hamburg similar to those performed by Prandtl in Hanover described in his 1904 article representing the birth of modern fluid mechanics with the all-important role of the boundary layer as the novelty, as described in The Dawn of Fluid Dynamics.

Ahlborn's motto was "Per experimentum et induction omnia" (everything is to be obtained inductively from experiments).

Ahlborn compared the boundary layer to a ball bearing, "like frictional rolls between the solid surface and the surrounding free flow", which he referred to as a "balanus layer" from the Latin word "balanus" meaning barnacle. Ahlborn further identified in his photographs "tender cycloidal serpentines" supporting his view that the transitional space to the free stream at some distance from the surface was "filled with a long chain of vortices".

Ahlborn thus identified the same structures experimentally as we have identified as 3d rotational separation in computational simulations 100 years later, as described on The Secret of Flight.

We cite from The Dawn of Fluid Dynamics:
  • In the 1920s Ahlborn and Prandl became engaged in sometimes harsh scientific quarrels. Despite their common interest in the nature of the boundary layer and the mechanism of skin friction, their mentalities  as researchers had little in common. "Per experimentum et induction omni" Ahlborn's leitmotif, was not Prandtl's.... 

Is Scientific Truth Determined by Politicians?


Politicians deciding a scientific truth of CO2 global warming at the 2009 Copenhagen Conference. Notice that our Prime Minister (3) is skeptical but keeps quite.


Science and politics/society is closely intertwined, but is it even so that scientific truth is determined by politicians?

Yes of course you say: Just look at the climate science of CO2 global warming determined by the politicians of IPCC: Continuing burning fossil fuel will raise global temperature by catastrophical 3 C and thus has to be reduced to zero by 2050.

The real scientific evidence for the CO2 alarm is however nil.

But is this an exceptional case? Is truth in more fundamental areas of physics determined by science and scientists and not by politics and politicians?

You may, probably correctly, argue that Newton's 2nd Law is not determined by politicians, but what about quantum mechanics and relativity theory forming the foundations of modern physics?

Well, we know that Planck as an expression of the ambitions of the emerging German Empire in 1900 took on the task of solving the main open problem of classical physics of blackbody radiation, and knowing that a solution had to be delivered "at any price", gave up the most holy of all principles of physics of determinism in his resolution based on statistics. The emerging German Empire had to deliver a solution and it did, however at the price of giving up holy principles of physics. This was practical politics rather than true science.

We also know that Einstein was elevated to be the God of modern physics by Eddington in a grand gesture of reconciliation between England and Germany after the 1st Word War, which was further enforced by an enthusiastic reception in the US with relativity as the ultimate expression of modernity.  France remained skeptical to Einstein' science until the 1950s, joined by USSR, but with Einstein in the team the US could win the Cold War and so finally confirm the truth of relativity theory, as well as the statistical interpretation of quantum mechanics going back to Planck.

But few physicists of today claim to understand relativity theory, and less the 50% say that they believe in the statistical Copenhagen interpretation of quantum mechanics.

The 1st World War is known as The Chemist's war and the 2nd as The Physicist's War, both won by better science, some of which was actually true. What will science be without a war?

PS And what about the theory of flight? Was it determined by Germany in cooperation with US in the 1920s that the Kutta-Zhukovsky circulation theory explains the generation of lift under heavy protests from UK? Yes, that is the truth which is still valid.
   

Strindberg om Skapelsens Matematik


Den Bortglömde August Strindberg grävs förtjänstfullt fram i dagens Svd i en intressant artikel av författare Bo Gustavsson, som nära kopplar till The World as Computation:
  • De centrala texterna i ”Ordalek och småkonst” är de båda tankedikterna ”Rosa mystica” och ”Skapelsens tal och lagar”
  • De representerar en höjdpunkt i Strindbergs lyriska författarskap. 
  • Det är märkliga texter där han förenar matematik och mystik, naturvetenskap och spekulativ filosofi. 
  • Grundidén är att universum styrs av matematiska lagar, vilket ju även utgör premissen för modern vetenskap. 
  • Strindberg skulle kunna instämma i Einsteins uttalande att Gud inte kastar tärning.
  • Slumpen existerar inte i vårt ordnade kosmos utan där gäller matematiska talförhållanden både på mikro- och makronivå.
  • "Skapelsens tal och lagar" inleds med ett citat ur Leibniz ”Teodicé”: 
  • Calculat Deus et mundus fit (Gud planerar och världen skapas). 
  • Inspirerad av pythagoreiska tankegångar gör Strindberg Skaparen till en matematiker och geometriker som likt kabbalans Gud tänker universums grundstruktur:
Calculat Deus et mundus fit!; det är
uttolkat: Varde!
Varde med tal och med mått; så börjar
Skapelseverket.
Punkten är vila; den rör sig framåt, och
linjen är skapad.
Linjen s’en med sig själv den alstrar en
täckande yta.
Ytorna avla, och straxt den rummet
fyllande kroppen
Blivit en verklighet, försedd med tyngd och
med dragning.
Kropparne draga varann, de större de
draga de smärre;
Detta är kraft, den dragande kraft, som rör
Universum.
Kärleken kallas den ock, som håller Alltet
tillsammans;
Hatet det stöter ifrån; det söndrar, löser och
dödar. –
Rörelse alltså i tal och i skönmått är början
till livet.
  • Här anspelas på Newtons gravitationslag och Empedokles idé att två krafter styr tillvaron: kärleken och hatet. 
  • Det är en mäktig upptakt till en modern lärodikt. Utifrån ”Zohar”, kabbalans urkund, låter Strindberg talmystik bli ordningsprincipen i universum. Ett är Skaparens tal, oföränderligt och evigt detsamma. 
  • Två är fördelningens tal och tre är familjens, statens och rikenas tal. Sedan för han ett intrikat resonemang om matematiska relationer mellan avstånden från planeterna till solen i ”sfärernas harmoni”. 
  • Även materien styrs av talförhållanden och en ömsesidig dragningskraft mellan grundämnena som Strindberg i alkemisk anda uppfattar som erotisk-mystisk.
Läs och begrunda. Notera särskilt att statistik och tärningskast inte ingår i Skapelsen.


onsdagen den 19:e september 2012

Computation Connects Theory and Practice of Fluid Dynamics


The virtual computational wind tunnel bridges the gap between theory and practice of fluid dynamics.

The Epilogue of The Dawn of Fluid Dynamics, commented on in the preceding post, discusses the relation between science and technology, or between theory and practice, with focus on the development of fluid dynamics during the 20th century as the privileged science during two World Wars and Prandtl as the Father of Modern Fluid Mechanics:
  • Fluid dynamics benefited from the high expectations with which patrons in government and philanthropic foundations, at the armed forces and in the industry, regarded this science.
  • The community of international fluid dynamicists was a mix of practical engineers and academic scientists whose institutional affiliation varied from applied mathematics to mechanical engineering...regarding Prandtl as the founding father of their discipline. G. I- Taylor addressed him as "our chief" who deserved a Nobel Prize.
  • Prandtl confessed to a preference to this approach (practice rather than theory): "When faced with problems in mechanics, I slowly became a accustomed to "see" forces and accelerations in the equations or to "sense" then by tactile feeling.
  • In this book, we have described to what extent the gap between theory and practice was bridged in the age of Prandtl. Surprisingly, physics showed little interest in fluid dynamics.
The gap between theory and practice in fluid dynamics opened already at the start with d'Alembert's paradox and did not diminish under the influence from Prandtl but only got deeper. 

However, when it is now possible, as we show, to computationally solve the Navier-Stokes equations in direct simulation thus offering a virtual wind tunnel, theory and practice comes together for the first time. In particular the Secret of Flight can be revealed.    


tisdagen den 18:e september 2012

The Dusk of Fluid Dynamics


The Dawn of Fluid Mechanics by Michael Eckert (2006) is presented as follows:
  • This is the first publication to describe the evolution of fluid dynamics as a major field in modern science and engineering. It contains a description of the interaction between applied research and application, taking as its example the history of fluid mechanics in the 20th century.
  • The focus lies on the work of Ludwig Prandtl, founder of the aerodynamic research center (AVA) in Göttingen, whose ideas and publications have influenced modern aerodynamics and fluid mechanics in many fields. While suitable for others, this book is intended for natural scientists and engineers as well as historians of science and technology.
The book gives valuable information on Prandtl, his role as German scientist through two World Wars, and his role as Father of Modern Fluid Mechanics. We cite from Chapter 8 Prandtl, Fluid Dynamics and National Socialism:
  • The question how fluid dynamics fared under the new regime cannot be answered without closer inspection of Prandtl's own political attitude. Such inspection brings to the fore a most ambivalent relationship between science and politics. 
  • In November 1933, Prandtl expressed in a private letter to his brother-in-law his satisfaction that one can now "as a German carry the head higher again". 
  • Prandtl was more than willing to place his capabilities and his institute to regime's disposal and the regime appreciated and honored Prandtl for this service.
  • In contrast to physics and mathematics, which experience a decline as a result of Nazi politics, fluid dynamics flourished in the Third Reich.
  • The regime's interest in aerodynamics research soon manifested itself in terns of generous financial support. Aeronautical research experienced a boom which was believed to be impossible before 1933.
  • Göring declared to the congregated scientists in an address at a meeting of the German  Academy of Aeronautical Research "Fluid dynamics has to combine with Air Force research in order to clear the basic laws form application to the Air Force and to guide the development align new paths".
  • Göring and his ministry also made use of Prandtl's reputation for propaganda purposes...to portray Nazi Germany as a country where science was still in high esteem, despite the purge of Jewish scientists from the universities. There are no indications that Prandtl felt uncomfortable with this role...he informed Göring in a letter in December 1936 of the measures that will be taken in his institute "for the conversion of research at a beginning of war".
  • Prandtl, like many other strongly nationally minded Germans, was impressed by the Nazi's determination to free Germany from what they considered the manacle of the Versailles treaty.
  • Göring praised German aeronautical research although "the collapse of our empire after the end of the war has prevented this good tradition from being continued". Only "the resolution of our Fuhrer to restore for Germany the military authority robbed by the Versailles dictate" made it possible to follow this tradition once again. At such occasions, Prandtl often sat in the front row next to the highest authorities of the Nazi regime.
  • When the German Academy of Aeronautical Research met on March 1 1939, Prandtl was awarded in the presence of numerous foreign celebrities the "Hermann Göring medal", the Nazi's highest distinction for scientific merit in aeronautics.
  • In May 1937 Prandtl wrote to William Knight the former NACA representative in Paris "I believe that Fascism in Italy and National Socialism in Germany represent very good beginnings of new thinking and economics".  
  • Prandtl described Hitler as a "man of tremendous nerve" who admittedly "made himself a million people his bitter enemies, but on the other side eighty million people his faithful and ardent followers".
  • With regard to the "Jewish question" he argued "The struggle which Germany unfortunately had to fight against the Jews, was necessary for its self-preservation".
  • Prandtl was neither naive nor forced against his will to participate in "the propaganda mission" as he called his efforts to sell Hitler's plans for a new order to the scientific world.
One should maybe bear these sides of Prandtl's soul in mind when recognizing him as the Father of Modern Fluid Mechanics. Prandtl as scientist is further scrutinized in Dr Faustus of Modern Physics

Request for Re-Evaluation by AIAA of New Theory of Flight

A request has been sent to AIAA Journal Editor-in-Chief for a re-evaluation of the submitted article New Theory of Flight, which was rejected by an associate editor.  The reason put forward is that the new elements of the article were not subject to evaluation in an AIAA review process with the main objective of defending exactly the Old Theory questioned by the article.

The review process including referee reports and editors comments will be subject to an analysis in the spirit of Thomas Kuhn in the upcoming book The Secret of Flight.

Kutta-Zhukovsky-Prandtl Devoid of Physics

David Auerbach starts out in Why Aircraft Fly by:
  • The question as to the origin of lift is older than Newton who, himself, gave the wrong answer (see, for example, Toakaty [1]). The vortex theory of flight due to Zhukowsky [2], Kutta [3], Lanchester [4] and Prandtl [5], although doubted by few, appears to many so devoid of any direct experiential basis that there are constant attempts to understand why an aircraft really manages to remain aloft: the idea of a bound vortex with its circulation seems so passive, the explanation, so abstruse and complicated.
Read and contemplate! These are tough words about the Old Theory of Flight of Kutta-Zhukovsky-Prandtl. Are they true?

Hyperphysics: Bernoulli of Newton's Law for Lift?

The explanation of the generation of lift of a wing on the educational site Hyperphysics gives evidence of the depth of the crisis of present aerodynamics education:
  • Which is best for describing how aircraft get the needed lift to fly? Bernoulli's equation or Newton's laws and conservation of momentum? 
  • This has been an extremely active debate among those who love flying and are involved in the field. 
  • If the question is "Which is physically correct?" then the answer is clear -- both are correct. 
  • Both are based on valid principles of physics. The Bernoulli equation is simply a statement of the principle of conservation of energy in fluids. Conservation of momentum and Newton's 3rd law are equally valid as foundation principles of nature - we do not see them violated. 
  • This physical validity will undoubtedly not quell the debate, and this treatment will not settle it. But perhaps it can at least indicate the lines of the discussion.
We see two explanations of the generation of lift being presented, both expressing valid physics, but both being trivial as being self-evident: lift by lower pressure above (Bernoulli) or lift as reaction (Newton). This is true but carries no interesting information like any triviality.

Each proponent of an explanation can rightly accuse the other for presenting a triviality and so the proponents cannot meet, although they share equally valid trivial arguments.


Airbus: Free-Glide Approaches and Landing



Airbus presents on its web site as a Smarter Skies vision to use Free-Glide Approaches and Landing:

  • Allowing aircraft to take free glide approaches into airports would lower emissions during the overall decent and reduce noise during the steeper approach as there is no need for engine thrust or air breaking.
  • These approaches also would reduce the landing speed earlier, making shorter landing distances achievable with less runway needed.
To come up with designs allowing free-glide with reduced landing speeds, accurate computational simulation of the full aircraft at large angles of attack would be very useful. 

The open source FEniCS/Unicorn Navier-Stokes/slip solver for slightly viscous incompressible flow, seems to have the capability for such a task.

The Princeton Sailwing





















Double-cloth sailwing supported by trailing edge cable with lift an drag coefficients right.

From A Comparison of the Aerodynamic Characteristics of Eight Sailwing Airfoil Sections by M. Maughmer (1979):
  • The Princeton sailwing, which has been under development since 1948, is a unique, semiflexible wing intended to provide the practical ultimate in a light-weight, low-cost lifting surface suitable for a number of low- speed applications. 
  • Basically, the structural configuration of the sailwing consists of a leading-edge spar with attached ribs which ideally form a rigid framework supporting a trailing-edge cable in tension. 
  • A non-porous, non-stretchable cloth membrane, usually dacron, is then wrapped around the leading-edge and attached to the trailing-edge forming the upper and lower sail surfaces....it has been found that the aerodynamic efficiency of the sailwing can indeed approach that of a hard wing.
Compare with Chapter 5 From Circular Cylinder to Wing in The Secret of Flight.

Note that with a single cloth membrane, like an ordinary sail, the lift-to-drag ratio decreases from about 15 to 10 because of the effect of a one-sided leading edge (mast) to increase drag and decrease lift.  

måndagen den 17:e september 2012

How to Answer a Question You Cannot Answer


The question how a wing generates lift gets the following answer on Wikipedia under Lift Force:
  • There are several ways to explain how an airfoil generates lift. Some are more complicated or more mathematically rigorous than others; some have been shown to be incorrect.
  • Most of them are intended to explain the phenomenon of lift to a general audience. Several theories introduce assumptions which proved to be wrong, like the equal transit-time theory.
The idea, used by many agencies expected to have an answer like NASA or AIAA, is to say that the answer to be presented is suitable for a "general audience" and as such it is not the correct answer, while suggesting that there is a correct answer certainly known to the agency, but that this correct answer is not suitable for presentation to a "general audience". 

This is believed to be a very smart way of covering up that the agency does not really know any correct answer: Give an incorrect answer (and there are many to choose from) and claim that for sure there is a correct answer, which however is not suitable for the general audience. 

You can study this very clever and effective tactics in the preceding sequence of posts on Incorrect or Empty Flight Theory. Have fun.

PS1 One may compare with different answers to the question from where babies come, which can vary depending on the audience. The question has to be answered, in one way or the other, because it is a very good question, and even an incorrect answer is then an answer, but it is not science.

PS2 As an real-life illustration study my Interview with Glenn Research Center:
  • The correct theory of lift is fairly complex. saying that the answer is complex means just that ... it is complex, it isn't simple. But we know what it is.
  • Many people look for simple answers to questions, when the answer may not be simple. When the answer is really complex, people make simplifying assumptions so that they can get a simple answer. Unfortunately, with fluid mechanics, when you make simplifying assumptions you can get the wrong answer. That's what has happened with the incorrect theories and their inability to produce meaningful results.

Empty Flight Theory at Boeing

Boeing presents as a service to the community the following information on Forces of Flight/Lift/Basics:
  • Lift is the upward force that counteracts gravity and enables airplanes to fly.
  • Lift keeps birds, gliders, and airplanes aloft as they move forward through the air. Lift is also generated by the spinning blades of a helicopter.
  • Aerodynamic lift is based on Daniel Bernoulli’s Principle, which states that the pressure of a flowing fluid or gas decreases as its velocity increases. To take advantage of this, an airplane wing, like a bird wing, is designed with a distinctive shape called an airfoil. This shape creates the greatest possible lift for the airplane.
  • The shape of an airplane wing, the angle at which the wing meets the airflow, and the speed of the airplane all affect the lift.
This information is preceded by a friendly: 
  • Welcome to "Forces of Flight," a new Boeing program created to help classroom teachers to excite and engage students about science.
  • We hope that you will find this program helpful and interesting. 
  • We are proud to partner with teachers who are making the effort to inspire the next generation of scientists.
  • In addition to being informative, this program is intended to promote student inquiry by linking the information on the posters and web site to a series of classic hands-on physics experiments that demonstrate how the forces of flight actually work.
But what Boeing offers to young minds eager to understand why it is possible to fly, is not a correct explanation of the generation of lift, in fact no explanation at all: It is only a vague hint that somehow it is the shape of a wing that generates lift, which is directly contradicted by suggesting that it is maybe instead the angle of attack that gives (a symmetric wing) lift. 

None of the natural questions from the students can be answered this way which can only teach that science is a hopeless mess which cannot excite and engage students. 

The question then presents itself: Does Boeing know how a wing generates lift?

To check out I sent today the following mail to Boeing:
  • On the web site The Secret of Flight I present a New Theory of Flight (submitted to AIAA) giving a new explanation of the generation of lift and drag of a wing, which is fundamentally different from classical text-book theory.
  • My question: How does Boeing explain the generation of lift of a wing? 
I will report the answer. Here it is:

Thank you for your message to the Boeing Web feedback box. The best source of information on The Boeing Company and our products is our public website: www.boeing.com

You can find a great deal of information using the search tool. Try clicking on the “About Us” link, which will take you to pages on history and research assistance (including an aviation reading list and related aerospace sites).

Due to the high volume of requests we receive, we cannot provide any additional information or research assistance than what can be found on our public website.

Thank you for your interest in Boeing.

Kind regards,
Boeing Webmaster

Incorrect Flight Theory in Flight and Motion Book



In the 641 page grand scale educational text Flight and Motion The History and Science of Flying, we read on How an Airplane's Wing Creates Lift:
  • The shape of a wing, curved on top and flatter underneath, is called an airfoil. 
  • When it slices through air, some of the air rises up over the curved top of the wing and down the other side. 
  • The air that travels over the top of the wing speeds up and, according to a scientific law known as Bernoulli’s Principle, the pressure above the wing falls. In addition, air flowing over the wing is directed downward by the wing’s shape. According to another scientific law, Newton’s third law of motion, this downward motion of the air results in an upward motion of the wing. 
  • The force that pushes a wing upward is lift. If a wing is tilted up at the front, air is deflected downward even more powerfully by the curved top and also by the angled bottom of the wing. This produces more lift.
In this description lift is somehow generated by the shape of the wing. As explanation it is empty of content. Circulation is not mentioned. The reason can be that it is considered to be too complicated for younger minds, although it is the correct explanation but has to be x-rated. Another reason is that an explanation by circulation is not convincing at all, not even to already educated minds. 

Incorrect Flight Theory at Federal Aviation Adm


The Federal Aviation Administration presents in the basic text  Aerodynamics for Naval Aviators among Aviation Handbooks and Manuals, the following explanation of the generation of lift of a wing:
  • An important phenomenon associated with the production  of lift by an airfoil is the “circulation” imparted to the airstream.
  • The generation of lift by an airfoil is dependent upon the airfoil being able to create circulation in the airstream and develop the lifting, pressure distribution on the surface. In all cases, the generated lift will be the net force caused by the distribution of pressure over the upper and lower surfaces of the airfoil.
  • If the airfoil is given a positive angle of attack, changes occur in the streamline pattern 
  • and pressure distribution similar to changes caused by the addition of circulation to a cylinder. The positive angle of attack causes increased velocity on the upper surface with an increase in upper surface suction while the decreased velocity on the lower surface causes a decrease in lower surface suction.
We see that FAA teaches pilots that an airfoil somehow creates circulation which generates velocity difference and thus pressure difference above and below the wing and thus lift,  as the top level of the science of flight. But this is nonsense! Nothing is explained! The natural mystery of flight presenting itself to the innocent uneducated mind, is here only made deeper by introducing a physically incorrect casual connection between circulation and lift.  

Another piece of evidence that aerodynamics education is today in free fall with zero lift and only drag.

Incorrect Flight Theory at the Smithsonian


Let us take a look at how the Smithsonian National Air and Space Museum presents How Things Fly to 4-8th graders:
  • Using this poster, students can explore the fundamental physics of flight. 
  • Students will be able to describe how Bernoulli’s principle enables airplanes to fly.
  • Wings are designed so the air moving over the top of the wing is forced to speed up more than the air moving below the wing.
  • A common explanation of lift states that air moves faster over a wing’s curved upper surface because it has farther to travel than air moving under the flatter lower surface. This explanation is wrong!
  • How can an airplane fly upside down? Wing tilt is the trick. Tilting the upside-down wing upward forces the air traveling over the wing to speed up more than the air passing beneath the wing. The difference in air pressure results in lift.
  • Activities on the following pages (4-6) enable students to discover for themselves how moving air creates changes in air pressure and how Bernoulli’s principle is put to use in wing design. The results are often surprising! 
OK, so young students are taught that lift comes from lower pressure above, which does not come from longer distance above (wrong explanation!), but somehow from tilting at least for an upside-down wing. 

But this is confusing nonsense which does not explain anything. To say that lift comes from lower pressure above is a trivial tautology. To say that tilting forces the air to travel faster above without telling why and how, gives no information, only further mystery.

The fact that the National Air and Space Museum feeds to minds of interested students with nonsensical disinformation is one of many indications that present aerodynamics education has collapsed. Who is responsible? AIAA?

Compare with US Centennial of Flight Celebrated by Dead Theory.

PS Today I sent the following question to the Smithsonian:

  • On the web site The Secret of Flight I present a New Theory of Flight (submitted to AIAA) giving a new explanation of the generation of lift and drag of a wing, which is fundamentally different from classical text-book theory, see also Incorrect Flight Theory at the Smithsonian.
  • My question: How does the Smithsonian explain the generation of lift of a wing? 

I will report the answer.