lördag 15 januari 2022

KVA Talar till Barnen

Kungliga Vetenskapsakademien KVA har givit ut skriften Vetenskapen säger: Om Klimatet författad av bland andra Deliang Chen, professor i fysikalisk meteorologi vid Göteborgs universitet, med syfte att upplysa svenska folket

  • Syftet är att nå ut med vetenskapssamhällets samlade syn på en fråga som berör oss alla.
  • Att forskningen på senare år nått fram till en samsyn om klimatförändringarna tror Delian Chen inte alltid att allmänheten är fullt medveten om. 
  • Istället sprids ibland missuppfattningar om att det fortfarande råder oenighet inom vetenskapssamhället om hur det faktiskt förhåller sig.
  • Det är viktigt att känna till att det kapitlet är avslutat nu. 
  • Det är också viktigt att veta att det inte är för sent att agera och att allt vi gör påverkar klimatet. Ibland hör man att det inte spelar någon roll vad vi gör i Sverige, men det är inte sant. 
  • Varje ton koldioxid vi släpper ut har en påverkan.
Skriften stödjer detta budskap på följande sätt: 
  1. Det är obestridligt att människans påverkan, främst genom utsläpp av växthusgaser, har orsakat en global uppvärmning och andra förändringar i klimatsystemet.
  2. Klimatsystemet tar emot energi från solen genom att fånga upp solstrålningen, och blir av med nästan lika mycket energi igen genom att sända ut infraröd strålning (värmestrålning) till rymden. För närvarande är den infraröda utstrålningen runt 0,8 W/m2 mindre än solinstrålningen. Det är denna strålningsobalans som leder till den pågående globala uppvärmningen.
  3. De senaste 160 åren har den globala medeltemperaturen stigit med 1,1 grader. Det finns ingen annan vetenskapligt förankrad förklaring till detta än de ökande halterna av växthusgaser, främst koldioxid.
  4. Ofta beskrivs växthuseffekten, väldigt förenklat, som ett växthus där solstrålning lätt kan ta sig in medan värmen inne i växthuset har svårt att ta sig ut igen. Det medför en ökad temperatur i växthuset, se följande förklarande figur:
 

Kommentar: 
  1. Att påstå att något är obestridligt är inte ett vetenskapligs argument. I vetenskap kan allt bestridas och ändras om nya fakta tillkommer, till skillnad från religion eller juridik.
  2. Noggrannheten i mätning av in och utstrålning är inte tillräcklig för att avgöra en skillnad på 0.8 W/m2 när maximal instrålning är ca 1366 W/m2. 
  3. Noggrannheten av mätning av global medeltemperatur är inte mindre än 1 C (avläs en typisk termometer) varför påståendet om 1.1 C höjning saknar mening. Höjningen kan lika gärna vara 0.5 C eller 0.1 C dvs utan signifikans. Att säga att koldioxiden är orsaken till den eventuella höjningen, eftersom man inte vet någon annan förklaring, är inte heller något vetenskapligt argument eftersom säkerheten i påståendet verkat öka ju mindre man vet. Och vad är egentligen innebörden av global medeltemperatur?
  4. Bilden som ser ut som en barnteckning med sin eviga sol i övre hörnet ger en helt felaktig bild av jorden + atmosfären som ett växthus med tak som verkar reflektera (återstråla) både högfrekvent solstrålning och lågfrekvent infraröd strålning från jorden. Varför ger KVA en fysikaliskt helt felaktig missvisande beskrivning av den s k växthuseffekten? 
Sammantaget ger skriften intryck av att ha skrivits för förskolan. Varför riktar sig KVA till barnen med sin ovetenskapliga skrämselpropaganda? Jag har bett KVA om svar, som kommer att rapporteras.

Här kan vi jämföra KVAs teckning med en riktig barnteckning som illustrerar Solen, det Svenska Samhället samt Hotet från Koldioxidutsläpp:






torsdag 13 januari 2022

Back Radiation: Algebraic Fiction or Physical Reality? 2

This is a continuation of the previous post with focus on the unphysical nature of back radiation as expressed in Schwarzschild's two-stream model of radiative heat transfer taking the following form in a setting of a horisontal atmospheric layer connecting the Earth surface to outer space with $z$ a vertical coordinate representing optical distance:
  • $\frac{dU}{dz}=-U+B,$
  • $\frac{dD}{dz}= D-B,$
where $U$ is upwelling radiation and $D$ is downwelling radiation and $B(T)$ is upward/downward emission of radiation according Stefan-Boltzmann's law with $T$ temperature depending on $z$. Subtracting the equations, we have
  • $\frac{d(D-U)}{dz}=D-2B+U.$  (0)
We see a balance at a certain level $z$ between U as incoming radiation from below, D as incoming radiation from above and -2B as emission upward and downward. Discretizing $z$ into discrete levels/nodes $z_i=i*h$ with $h$ a mesh size and $i=0,1,2...$, the balance of upward and downward radiation involves  
  • $B_{i+1}-2B_i+B_{i-1}$    (1)
with $B_i=B(T(z_i))$, if we set $B_{i+1}=D(z_{i+1})$ and $B_{i-1}=U(z_{i-1})$. 

We will now compare (0)-(1) with the following discretised heat equation for a temperature $T(z,t)$ with $t$ a time coordinate:
  • $dT_i/dt = (T_{i+1}-2T_i+T_{i-1})*\frac{1}{pow(h,2)}$   (2)
where $T_i=T(z_i,t)$, which is a discretisation of $\frac{\partial T}{\partial t}=\frac{\partial^2 T}{\partial x^2}$. We know that the heat equation is a stable physical model subject to perturbations $p$ of (2) of the form
  • $dT_i/dt = (T_{i+1}-2T_i+T_{i-1})*\frac{1}{pow(h,2)}+p$.    (3)
while perturbations $P$ of (1) would have the form
  • $B_{i+1}-2B_i+B_{i-1}+P$.    (4)
We see that introducing a perturbation $P$ of the form (4) in (2) would correspond to a perturbation $p=\frac{P}{pow(h,2)}$ which would be big since $h$ is small. We thus see a fundamental difference as concerns stability between a heat equation of the form (2), which is stable, and a two-stream model of radiative transfer of the form (0). 

Note that the idea of two-stream radiative heat transfer with upwelling/outgoing (longwave) radiation OLR and downwelling (long wave) DLR is firmly implanted in the discussion of the GHE through the two-stream Schwarzschild model. In particular, the existence of DLR is supposedly being demonstrated experimentally with the help of a pyrgeometer, which however is a ghost detector. 

Back Radiation: Algebraic Fiction or Physical Reality?

The physics of a "greenhouse effect" (GHE) resulting from "back radiation" from a colder atmosphere with "greenhouse gases" (GH-gases) to a warmer Earth surface, is still a subject of active discussion. A recent contribution is Verification of the Greenhouse Effect in the Laboratory by Hermann Harde and Michael Schnell published in Science of Climate Change, presenting the following main points:

  • The impact of the different greenhouse gases (GH-gases) on our climate is not really well understood and even under experts this repeatedly leads to doubts about its existence and its influence on our climate.
  • This article summarizes the theoretical background of the GHE and presents first quantitative measurements of this effect with an advanced experimental set-up. 
  • For our studies we use an experimental set-up, which consists of two plates in a closed housing, one plate heated to 30 C, the other cooled to -11.4 C. 
  • ...the set-up...uses a heated plate as radiation source and simultaneously as sensitive detector for the back-radiation from GH-gases. We measure the increasing temperature of this plate or, alternatively at stabilized temperature, the energy saving due to the back-radiation.
  • We measure the additional warming of a pre-heated plate due to back-radiation of the greenhouse gases carbon dioxide, methane and nitrous oxide as a function of the gas concentration, and we derive from the observed warming the radiative forcing of these gases.
  • Our studies also demonstrate that contrary to the often-misinterpreted 2nd law of thermodynamics a warmer body can further be heated by absorbing the radiation from a colder body, here the radiation from the cooled plate and a GH-gas.
  • In addition and independent of the temperature measurements is the back radiations of the GH gases directly recorded as reduced electrical heating of the upper plate.
  • These measurements clearly demonstrate that contrary to the often misinterpreted 2nd law of thermodynamics a warmer body can further be heated by absorbing the radiation from a colder body, here the radiation from the cooled plate and a GH-gas.
  • The presented measurements and calculations clearly confirm the existence of an atmospheric GHE, but they also demonstrate the only small impact on global warming with increasing GH-gas concentrations, which in any way are apperently dominated by natural emissions. So, there is no reason for panic and climate emergency.
The article claims to give the first verification of GHE in a laboratory setting with measurements supported by theory in the form of Schwarzschild's two-stream equation for radiative heat transfer. GHE is viewed to be an effect of back radiation with a warmer plate absorbing radiation from a colder plate, yet without violation of the 2nd law of thermodynamics. 

I have agued (see also video) that back radiation with two-way radiative heat transfer is unphysical and should be replaced by one-way transfer from warm to cold, with recent detailed follow up by Joseph Reynen. The presence of back radiation is directly connected to Schwarzschild two-stream model, which is described as follows in standard treatise Atmospheric Radiation: Theoretical Basis by Goody and Yung: 
  • While it sets the pattern of the formalism used in radiative transfer problems, its physical content is very slight.
  • The Schwarzschild-Schuster approximation is now of historical interest only.
The key issue concerning back radiation and Schwarzschild's two-stream equation is as follows: Stefan-Boltzmann's equation (SB) for one-way radiative heat transfer $Q$ between two bodies $B_1$ and $B_2$ of temperatures $T_1$ and $T_2$ with $T_2>T_1$ takes the form
  • $Q =\epsilon\sigma (T_2^4-T_1^4)$      (1)
with $\sigma$ Stefan-Boltzmann's constant and $0<\epsilon \le1$ a coefficient depending on the nature of the bodies with $\epsilon =1$ for black bodies. Algebraically the SB equation can formally be written 
  •  $Q = \epsilon\sigma T_2^4 - \epsilon\sigma T_1^4$    (2)

expressing two-way transfer with $\epsilon\sigma T_2^4$ heat transfer from $B_2$ to $B_1$ and $\epsilon\sigma T_1^4$ heat transfer from $B_1$ to $B_2$.  We see that (1) expresses $Q$ as net transfer from warm to cold, which in (2) is formally written as the difference between two gross transfers back and forth between warm and cold. 

Implicit in (2) is Kirchhoff's Law expressing that absorptivity is equal to emissivity since in (2) the coefficient $\epsilon$ has both the role of emissivity and absorptivity depending on the interpretation of (2) as both heat balance for $B_1$ absorbing heat from $B_2$ while emitting heat to $B_2$, and heat balance for $B_2$ absorbing heat from $B_1$ while emitting heat to $B_1$. 

Algebraically (1) and (2) are formally the same but the physics is different with one-way net heat transfer in (1) and two-way difference of gross heat transfer in (2). Now comes the key observation: From stability point of view (1) and (2) are not the same: A percentagewise small perturbation of net transfer will result in a small change of net transfer, while a small percentagewise perturbation of gross flow may result in a big perturbation of net transfer. 

One can now argue that physics must be stable to persist over time and so two-way radiative heat transfer as expressed by Schwarzschild's two-stream equations is unphysical and that is also what Goody and Yung says. 

It thus remains to find a mathematical model for one-way radiative heat transfer and here the stack model studied by Reynen is a first step. In a next post I will exhibit the crucial aspect of stability in a simple example comparing from stability point of view Schwarzschild's unphysical two-stream equations with a physical heat equation. 


onsdag 27 oktober 2021

Energy Power Politics: China vs US/EU

A basic postulate of Mearsheimer's offensive realism expressed in The Tragedy of Great Power Politics says that states attempt to maximise their power at the expense of other states with survival as ultimate goal.

Great power politics is played with economical and military force both ultimately resting on supply of energy. 

China is now increasing its energy production with a new coal plant opened every week.

All 27 EU Member States are committed to turning the EU into the first climate neutral continent by 2050.

President Biden is pledging to reduce U.S. greenhouse gas emissions by at least 50% by 2030.

This is the set-up for the UN Climate Change Conference COP26 in Glasgow starting next week: China will continue to build economical and military power from fossil energy, while EU/US will phase out fossil energy without possibility to compensate by new nuclear energy.

From an offensive realist point of view with survival as ultimate goal, this does not look good at all for EU/US. Clearly EU/US politicians do not listen to Mearsheimer, only Xi.     


fredag 8 oktober 2021

Styrs Skolan av Läromedelsföretagen?

Statistik från Läromedelsföretagen visar att Skolan till Läromedelsföretagen betalar 500-1000 kr (snitt 650 kr) ca 0.5% av totalkostnaden per år och elev. Det ger en stor läromedelsmarknad om minst 650 miljoner kr att dela mellan läromedelsjättar som Gleerups, Studentlitteratur, Liber och Natur och Kultur. 

För huvudämnet matematik skulle då kanske varje elev per år få tillgång till läromedel för 200 kr. Hur mycket lärdom kan det rymmas inom en sådan ram? Räcker det? Inte i alla skolor tydligen, eftersom många lägger det dubbla, förmodligen för att det krävs. Men kanske inte ens det räcker för att ge alla elever tillgång till rikt material för utveckling och förkovran.

Skolans undervisning verkar styras av läromedelsföretagen som producerar och säljer läromedel med speciellt funktionalitet som gör att läraren i detalj kan övervaka varje elevs prestation uppgift för uppgift minut för minut, vilket då kan bli lärarens huvuduppgift eftersom det utmärkta läromedlet sköter själva undervisningen. Matematikämnet är särdeles lämpat för denna övervakade detaljstyrda utbildning. Men kanske är det inte det bästa för vare sig elev eller lärare.

Här erbjuder Leibniz World of Math ett alternativ i form av konkret realisering av den nya läroplanen i matematik+programmering i form av:  

  • open textbook fritt tillgänglig utan kostnad,
  • ny skolmatematik som konstruktiv matematik för en digital värld,
  • sammanhållet rikt program från förskola till högskola där eleven själv bygger matematik 
  • utvecklat av högsta akademiska kompetens.
Som Rektor, testa vad Leibniz WoM kan ge Dina Lärare.
Som Lärare, testa vad Leibniz WoM kan ge Dina Elever.
Som Elev, testa vad Leibniz WoM kan ge Dig själv.


tisdag 5 oktober 2021

Nobel Prize in Physics to Climate Models which Do Not Model Climate

The Nobel Committee in Physics has as an act of scientific political correctness today given half of the Nobel Prize in Physics in 2021 to Syukuro Manabe and Klaus Hasselmann for the physical modelling of Earth's climate quantifying variability and reliably predicting global warming.

In other words, the Prize has been given to Climate Models which Do Not Model the Climate, as is shown in the following graph of Global Warming over time comparing Climate Model predictions with Real World observations (second image from Roy Spencer Global Warming) : 




These graphs must have been unknown to the Committee. What is the meaning of "reliably predicting global warming" when the prediction has nothing to do with the actually observed absence of observable global warming (0.2 C over 40 years)? Is the "reliability" that all climate models show too much warming, or that the spread is so big that even virtually no warming is included in the predictions?

fredag 24 september 2021

Kritik av Skolverket i Ny Avhandling om Matematik+Programmering

Peter Vinnervik ger Skolverket svidande kritik i sin avhandling om den nya kursplanen med programmering som del av matematikämnet, vilket tas upp i artikeln Forskare: Skolverket är otydliga om programmering i Läraren:

  • Skolans styrdokument ger inte lärarna tillräckligt bra stöd för hur de ska undervisa i programmering.
  • Man talar om att eleverna ska lära sig programmeringens grunder, men vad de består av kommuniceras väldigt kortfattat i kursplanerna, framför allt för ämnet matematikbudskapet om programmering kommuniceras via flera olika texter. 
  • Man är väldigt otydlig med vad det är för kunskaper som eleverna ska lära sig. 
  • Lärarna upplever budskapet som väldigt luddigt.
  • Det behövs ytterligare en revidering av kursplanerna för att göra det tydligare för lärarna hur de ska arbeta med programmering i undervisningen.
Peter Vinnervik går så långt att han föreslår att programmering skall överföras till teknikämnet, eftersom reform av matematikundervisningen förefaller vara utsiktslös. 

Vi får se om Skolverket kan lyssna på denna kritik. Skolverkets syn uttrycks av undervisningsråd Johan Falk, som i Läraren uttrycker Skolverket: Ge mattelärare tid att fortbilda sig i programmering:
  •  Studiematerial och tillfällen till fortbildning i programmering finns. 
  • Flaskhalsen är tid och den är det bara skolhuvudmännen som kan skapa för sina lärare.
Innebörden är att Skolverket inte anser att Skolverket kan göra något mer än det som redan gjorts. 

Det skall bli intressant att se om Skolverket är kapabelt att lyssna på något av den svidande kritiken från Vinnervik. Det är inte säkert. Som Skolverkets Generaldirektör Peter Fredriksson urskuldande brukar säga: "Matematik är inte Sveriges bästa gren".

From Vinnervik's Abstract:

The results show that teachers face several intrinsic and extrinsic challenges during the process of integrating programming in their teaching. A perceived lack of professional knowledge and understanding of programming among the teachers emerged as a prominent challenge both prior to and more than two years into the reform. Additional challenges are related to teaching materials, time for preparation and professional development. In technology education, teachers mainly see programming as a medium to explore and understand technological systems and construction work. They are uncertain of what programming means in terms of practices and concepts, and about learning progression and assessment. The results further reveal that the curriculum texts are sparse on details about what programming knowledge entails. Important strategic decisions are left entirely to the teachers without any clear guidance. In addition, the results indicate that many technology teachers work in isolation and that interdisciplinary work around programming, as intended in the curriculum, is generally lacking. It is concluded that there is a risk of inequality among schools and that the children’s experience of programming becomes fragmented, despite good intentions. The current implementation model needs to be improved, and this thesis presents two possible actions.


måndag 20 september 2021

New Math Education Site: Leibniz World of Math

I have changed the name of my mathematics education project to Leibniz World of Math from the previous DigiMat Encyclopedia. Take a look! 




fredag 17 september 2021

Euler Was Right, Prandtl Was Wrong II

I am working on a new article to be expanded to a book with the title Euler Was Right, Prandtl Was Wrong  which can be seen as a summary of my work on fluid dynamics for 30 years together with former students Johan Hoffman, Johan Jansson and Anders Szepessy. In short, our work shows that the following prophetic declaration by Euler from 1755, indeed is fully correct:

  • My two equations contain all of the theory of fluid mechanics. It is not the principles of mechanics we lack to pursue this analysis but only Analysis (computation), which is not sufficiently developed for this purpose...We have to wait until the age of the computer to solve the equations.
And yes, we now live in the age of the computer and then Euler's two equations as a parameter-free model can be solved in the form of Euler CFD (Computational Fluid Dynamics) and so open a whole new world of turbulent flow to prediction, analysis and control, without any further need of mathematical modeling with parameter fitting. 

Euler CFD is to be compared with Prandtl CFD as the Standard CFD developed during the 20th century based on Prandtl's boundary layer theory including complicated wall and turbulence models with many parameters, which does not offer true predictive computation, as the legacy of the declared Father of Modern Fluid Mechanics

Take look and see what you think. This post directly connects to the discussion in recent posts with Doug McLean representing Standard CFD. See also previous post.

onsdag 18 augusti 2021

Corrections to Key Statements by Aerodynamics Expert McLean

Below follows corrections by Doug McLean to my attempt to collect Key Statements by Aerodynamics Expert Doug McLean. As before my comments are in italics in parenthesis.

Do the statements in your summary give correct expression of my views? For the most part, no:

"1. Flight is perfectly understood because fluid flow obeys the RANS equations."

Your comment: "1 is empty: Perfect understanding does not come from looking at RANS numbers. "

This isn't how I would put it. I'd say lift is perfectly understood in a scientific sense because the RANS equations with a no-slip BC and a good turbulence model correctly model the physics of the flow point by point, and solutions to the equations yield the right global flow patterns and flow details. The good agreement with reality verifies that the principles embodied in the equations are the right ones. Thus I say lift is perfectly understood in a scientific sense because we know what principles apply point-by-point in the flow, and we know that to make global predictions, all we have to do is solve a set of PDEs. So the understanding provided by RANS is based on a lot more than "looking at RANS numbers".

"2. Qualitative explanation(s) of lift (are) not essential to the science, and their faults don't contradict my assertion that the science is well understood."

This one is true.

"3. No-slip is enforced in physical terms because the required force arises naturally from the solution to the viscous-flow equations."

C"3 is misunderstanding of the difference between real physics and mathematics."

To conclude that I misunderstand this you have to misrepresent what I said. I was responding to your claim that the no-slip BC is "unphysical" because it contains no explicit reference to a force, and a force would be required to enforce the zero velocity. I replied "Of course forcing the fluid to have zero velocity at the wall requires some applied force, but the required force arises naturally from the solution to the viscous-flow equations." Any reasonable person would agree that both of us, in referring to "force" and "velocity", were referring to the theoretical world modeled by the equations, not to actual physical flows. To accuse me of saying that a mathematical equation can cause a force to arise in the real world is absurd.

"4. New Theory and RANS are equally "deficient" in the sense of failing to provide to a "qualitative" understanding of flow patterns."

Your comment: "4 is misunderstanding of New Theory."

I stand by this one. Your counterargument: "The New Theory comes with an explanation of the generation of large lift at small drag as a consequence of the general explanation of slightly viscous incompressible bluff body flow as potential flow modified by 3d rotational slip separation." is gobbledygook that explains nothing and fails to answer qualitative questions such as why pressure differences and changes in flow velocity appear in the field, and how "3d rotational slip separation" actually modifies the flow. 

(Doug admits that New Theory of Flight to him is "gobbledygook", which means that he has not understood. To dismiss something on the only ground that one does not understand, is not the way science is to be performed. The New Theory is not hard to understand since it builds on (i) potential flow modified by (ii) 3d rotational slip separation. I ask Doug: What is it that is  "gobbledygook" with (i) + (ii)?)  

"5. Headline of Scientific American 2020 (is) sensationalistic nonsense."

This one is true.  (This is a most remarkable statement.)

"6. There is no need of New Theory, even if it happens to be correct, because there are already many theories (for different audiences) which are (even if not correct) by the aeronautical/scientific community agreed in broad consensus to model lifting flow correctly to their respective levels of physical fidelity."

No. There is no need of New Theory, even if it happens to be correct, because RANS and all the simplified theories related to it (in retrospect derivable from RANS with simplifying assumptions) already provide our understanding in a scientific sense. The qualitative explanations for different audiences aren't really part of our scientific understanding, as I've explained to you more than once. (Also most remarkable)

"7. New Theory (might) make a contribution for (massively) separated flow."

Perhaps. We'll see.

The no-slip condition also came up in a previous note where you said:

"You say that slip at the wall is fiction, yet you present in your book a turbulent bl in Fig 4.1.14 which meets the wall with effectively slip. Contradiction."

There's no contradiction. On an airliner wing in cruise, the thickness of the viscous sublayer is typically less than 0.2% of the thickness of the TBL, over most of the chord. So the sublayer is too thin to be seen on the scale of plots like fig 4.1.14. But the sublayer is real, and it obeys no-slip at the wall. Modeling it realistically with no slip, as most RANS codes do these days, is preferable taking the shortcut of a slip BC.

"You say that no-slip is a physical boundary but you do not answer my question how in physical terms you can control fluid particles to have zero velocity."

I did answer the question, but you twisted my answer beyond recognition in your response to item 3 above. In an actual physical flow, forces internal to the fluid arise naturally (pressure forces, viscous forces, and Reynolds stresses), and these forces can produce the accelerations needed to meet the no-slip condition. When we model this mathematically, these forces are modeled in the equations that apply throughout the field. This is the basis for my statement in item 3 above. I'm not saying that the equations "control" the flow; I'm saying that actual physical forces control the flow. No-slip is a valid BC for the equations. There's no need for force to appear explicitly in the BCs, as you seem to believe.

"What is the physics on a microscope level that realises no-slip? "

See p. 15 of my book for a simplified explanation. (Why simplified? What is a real explanation?)

Conclusion: Your blog page "Key Statements by Aerodynamics Expert Doug McLean" misrepresents most of my statements. Please revise it to reflect more accurately what I've actually said. 

(Let me here try with a new short summary of McLean's views):
  1. Lift is perfectly understood in a scientific sense because the RANS equations with a no-slip BC and a good turbulence model correctly model the physics of the flow point by point, and solutions to the equations yield the right global flow patterns and flow details.
  2. Qualitative explanation(s) of lift (are) not essential to the science, and their faults don't contradict my assertion that the science is well understood.
  3. Forcing the fluid to have zero velocity at the wall requires some applied force, but the required force arises naturally from the solution to the viscous-flow equations.
  4. New Theory is gobbledygook.
  5. Headline of Scientific American 2020 (is) sensationalistic nonsense.
  6. There is no need of New Theory, even if it happens to be correct, because RANS and all the simplified theories related to it (in retrospect derivable from RANS with simplifying assumptions) already provide our understanding in a scientific sense.
  7. New Theory might perhaps make a contribution for (massively) separated flow.
(Let's see if McLean accepts this as a summary of his views. On 7: All bluff body flow (wings, airplanes) is (massively) separated flow.)

Question to Doug:
You admit that New Theory of Flight is "gobbledygook" to you, which means that you have not understood. To dismiss something on the only ground that one does not understand, is not the way science is to be performed. The New Theory is not hard to understand since it builds on (i) potential flow modified by (ii) 3d rotational slip separation. What is it that is "gobbledygook" with (i) + (ii)?)

Answer by Doug: 
You've taken what I said our of context. This comes from my response to your item 4, which specifically referred to the fact that CFD calculations, including both RANS and your New Theory, don't provide any "qualitative" explanation of flow patterns, the kind of explanation that would be understandable to a non-technical person. 

Your response was gobbledygook in the sense that a non-specialist would have no idea what you're talking about. I also stand by my statement that, even to a specialist, it doesn't explain anything about lift in a qualitative flow pattern sense. 
 
No, I understand your New Theory just fine. I just contend that it hasn't added anything to our understanding of lift.

My new questions:
  1. So the theory is not "gobbledygook" to you, only to a "non-technical person"?
  2. Ok Doug, you say you understand New Theory. I then ask you: Do you think New Theory is correct or not correct? If not, what is wrong? 
  3. What qualitative flow pattern would you like to see explained, which you do not find in the New Theory? Attachment on top? Separation without pressure rise at trailing edge? Large lift at small drag? 
Answers by Doug: (with new question (Q1)-(Q7) in parenthesis in italics)

Yes, I think I understand how the New Theory models the physics, and I think it's incorrect. I've given detailed reasons in previous notes, so I won't repeat them. Regardless of the details, one bottom-line result suffices to show that the New Theory is deficient: According to the New Theory, the pressure drag of a streamlined body without the induced drag associated with lift in 3D (e.g. 2D NACA 0012 at zero lift) is at least 80% of the total, with skin friction less than 20%. Experimental measurements of skin friction on many kinds of streamlined bodies, including airfoils and wings, contradict such a low level of skin friction and support the higher levels predicted by traditional models.

(Truth is that experiments for NACA0012 at zero angle of attack shows C_D = 0.006 without tripping and C_D = 0.008 with artificial tripping, while Euler CFD with zero skin friction gives C_D = 0.006 in close agreement with experiments without tripping. Now, a wing on an airplane does not have a tripping device (ribbon) on the leading edge, and so Euler CFD matches the real case. What is then the role of tripping in the experiment, when the real case does not have tripping? (Q1)

The motivation given in the standard literature is that the the ribbon is there to guarantee that the boundary layer is turbulent and so does not separate until the trailing edge, which follows from an expectation that a laminar boundary separates early. Is this also your answer? (Q2)

With tripping C_D increases with 0.002 which can be seen as an effect of changed geometry with a turbulent wake after the ribbon as additional form drag, which is identified as skin friction drag. Do you see that it is not so clear how to distinguish between form drag and skin friction drag in tripped experiments? (Q3)

If now the effect of tripping is to increase skin friction contribution to C_D with 0.002 as an effect of a turbulent boundary layer, what does that say about skin friction contribution without tripping? Still dominating? If tripping adds 0.002 skin friction, how much skin friction is there without tripping, smaller or bigger than 0.002? (Q4))

And here I'm talking about conventional calculations for which the turbulence model was calibrated to flat-plate TBL data and used unaltered for everything else, on whatever portion of the surface that the BL was predicted to be turbulent. Your claim that conventional methods can't predict drag correctly for wings, etc. unless the turbulence model is tuned on a "case-by-case" basis is false.

(No, Doug Standard CFD with wall and turbulence models contain parameters which are determined on a case-by-case basis. Do you really claim that there is one choice of parameters for all cases? If so, where can I find the values of these parameters? (Q5))

Your reasons for rejecting the conventional theories at other levels (circulation theory, lifting line, BL theory, etc.) are also false, in my opinion.

I'm not alone in this assessment. You've had some years now to make your case, and it seems you've convinced very few, if any, of the cognoscenti in the field. As a counter to this general line of argument, you could cite the example of plate tectonics, which was widely rejected in its field for many years before finally becoming the dominant paradigm. Given the evidence I've seen, however, I'd say the New Theory has practically zero chance of becoming the plate tectonics of high-Re aerodynamics.

What qualitative flow pattern would I like to see explained, which I do not find in the New Theory? Just about any qualitative feature of the flow: flow turning, changes in flow speed, differences in pressure, etc. You can observe these things in your numerical solutions, but that doesn't explain in a qualitative cause-and-effect sense how they come about. The New Theory is similar to conventional CFD in this regard.

(No Doug, if you do not see that New Theory explains large lift at small drag in physical terms as (i) attachment because the flow is potential before separation, and (ii) 3d rotational slip separation without pressure rise at trailing edge, then you have not understood the physics of New Theory. What is it with (i) and (ii) that you do not understand? And if you understand (i)+(ii), what is it that you do not understand concerning consequences of (i)+(ii) on lift and drag? (Q6))

You know where I stand. I think the other Wikipedia editors have already made a valid case for not including the New Theory in the lift article. I hope that their arguments prevail and that I won't have to take part in that discussion.

(You did not take part in the Wikipedia discussion, where only so called hobbyists participated, which prevented any form of technical discussion. Why did you not participate, when you effectively serve as expert behind the Wikipedia article? (Q7))

Answers by Doug:

You continue to misread and ignore my answers. Regarding the NACA 0012, the New Theory predicts C_D = 0.006, which agrees with experiment. But you also claim that skin friction represents only 20% of that total drag. That would be an average skin friction of 0.0006 on each surface, about the same as attached laminar flow on a flat plate. When I point out that such a low value is contradicted by "Experimental measurements of skin friction" under turbulent conditions, you deflect the conversation back to the total drag. On the airfoil we know from experimental measurements that the boundary layer becomes turbulent, either at a trip or farther aft by natural transition (untripped case). In both cases the average skin friction is significantly higher than the laminar flat-plate level. The fact is that the new theory gets the total drag right but apparently misses the average skin friction part badly for the untripped case. Conventional CFD gets both parts right, for both the tripped and untripped cases.

(Euler CFD with zero skin friction gets untripped C_D correct (=0.006) within measurement accuracy, with thus form/pressure drag = 0.006. Standard CFD claims 50-80% skin friction drag which with the same total  drag means that form drag is max 0.003 = max 50 percent of form drag from Euler CFD. The reason is probably that Standard CFD does not catch the correct separation (too high pressure at the trailing edge) and so gets too small form drag. Standard CFD in this respect resembles potential flow separation with pressure rise at separation and zero form drag.)

And you're wrong about turbulence models needing to be adjusted "case-by-case". Turbulence models vary widely in quality. There are bad ones that probably do need case-by-case adjustment. Perhaps this is what misled you to think that this is generally true of turbulence models. But it isn't. Good turbulence models don't require case-by-case adjustment. I know this from decades of experience using several different turbulence models. 

(How do you distinguish good turbulence models from bad?)  

Your new questions Q1-Q7 have easy answers, none of which would support your arguments. But, given that you don't seem to actually read my answers, I think continuing to answer your questions would be pointless, so I'm stopping here. My joining a technical discussion on Wikipedia would be equally pointless.

(Ok, it seems that our discussion has come to an end since you do not want to answer my Questions Q1-Q7. But the question "what keeps planes in the air" remains to be answered and this will form next headlines in Science and Nature. I want to thank you for your participation displaying the state of modern fluid mechanics, which will serve an important role as reference in the scientific discussion, which will continue until basic questions have found answers. This is the way science works, or is supposed to work. Best regards, Claes.)