There have been many theories presented in last 100 years or so, to explain the physics of lift force generation by an airfoil wing. These were erroneously centered around streamlined and laminar flow concepts, all of which were derived from wind tunnel experimentation and various applications of Newtonian forces and Bernoulli’s principle and were the main reason which resulted in failure of Albert Einstein when he was contracted to design a high performance wing for a German aircraft manufacturer of that time. These inapplicable concepts always hid the actual physics and mislead the researchers from fully understanding true causes of lift, in the real world. The new zone theory of lift, presented below, completely does away with this flawed science, and not only explains the true origins of lift but also several other aerodynamic characteristics of aircraft e.g., slat action, reason for stall, etc. All these topics are covered in detail in the eBook.
The fundamental assertions or postulates of the New Zone Theory of Lift, are as under. Refer to the figures on this page to aid in visualizing the concepts presented in the postulates.
Postulate-1
Aerodynamic Lift is not the result of any kind of reaction force on wing due to its angle of attack. Lift is the vertical component of the pneumatic suction force F-aero which acts perpendicularly to the Inductor Surface of the airfoil.
F-aero resolves into the vertical lift vector and a horizontal vector F-exp or expansion force. This expansion force F-exp is countered by thrust which causes expansion of air above the airfoil inductor surface.
All the energy produced by the engines goes into expanding the air in the induction zone, and a much smaller fraction of the thrust is used in overcoming the friction or drag.
Postulate-2
An airfoil wing moving in air creates two distinct regions of different pressures, over its top surface. These are called the forward Subduction-Zone and the rear Induction-Zone. The Subduction-Zone is a region immediately around the leading edge, and extends backwards up to the zero-slope line on the airfoil. The pressure in the Subduction-Zone is above atmospheric pressure. The Induction-Zone is a region of less than normal atmospheric pressure between the zero-slope line and the trailing edge. These pressure zones are illustrated in figure above. The creation these two zones by a moving object is a manifestation of the Salman Effect.
Postulate-3
During flight there is no flow of any kind, either streamlined or laminar over and under an air foil wing. For all practical purposes, the air mass surrounding the wing is stationary. Consequently, the aerodynamic lift generation action of the airfoil is not attributable to any kind of motion of air.
Postulate-4
There is essentially random turbulence on the top surface of an airfoil wing i.e., between the leading and trailing edges, as shown in figure below. This is due to the random motion of the atmospheric air mass which rushes in rapidly towards the wing from all directions, to normalize the pressure back to atmospheric conditions.
Postulate-5
There’s no such thing as a boundary layer adhering to the wing surfaces. Even if there is, it doesn’t take any part in lift generation. Unlike water, air does not wet the wing.
Postulate-6
The Coanda Effect applies to air flowing over still objects, but not to objects moving in still air. The Salman Effect of Aerodynamics relates to the creation of two distinct regions of different pressures, one called the Subduction-Zone ahead of a moving object, and the other Induction-Zone behind the same object. The forward Subduction-Zone has higher then atmospheric pressure, and the rear Induction Zone has a less then atmospheric pressure.
For the case of the airfoil, the Induction Zone is in the space immediately over the rear slope or the Inductor surface of the wing. The Subduction-Zone is created immediately ahead of the leading edge, as shown in figures above in the beginning.
Airfoil Lift Generation Action
Something wonderful happens when an airfoil (aircraft or bird) starts to move in air. The process of generation of lift by the airfoil is as follows. When the aircraft moves a Subduction Zone is created in the air mass near the leading edge. The Deflector physically pushes the air in the Subduction Zone away from the leading edge in different directions. Of particular importance is the repulsion of air upwards above the zero-slope line, or point C in figures above. In doing so it creates rectangular-slot shaped opening in the air mass for the rest of the wing to move in with least resistance.
Thereafter as the airfoil further penetrates past the zero-slope edge into the Subduction-Zone, its Inductor now starts to further rarefy the air over itself, creating the Induction-Zone of less than atmospheric pressure. This happens exactly as predicted by the Salman Effect. The wing experiences an upward force due to relatively higher atmospheric pressure underneath, as shown in above figure.
The constant recession of the Inductor Surface to create a pressure drop is analogous to the rotating vane of a rotary vacuum pump. The difference is that the vane of the rotary pump rotates in the cavity to create the vacuum or low pressure behind it, whereas the wing moves linearly forward in the imaginary conduit, reducing the pressure behind it as shown in above figure. The action in both cases is to expand and compress the air behind and ahead of it, respectively. So far so good? Yes, but wait … there’s still some mystery to be solved ahead, as mentioned in the thermodynamics and energy conversion involved in this forced expansion by the inductor of the airfoil.
Approximation of an enclosed transient conduit by the finite transit time of air-mass to refill the void:
The mass of air in the Induction-Zone certainly experiences expansion and negative work similar to a mass of gas in an enclosed cylinder fitted with a receding piston. But no such container boundaries are present in the atmosphere.
So how is such expansion even possible in open atmosphere over the wing, and generate low pressure?
The answer is that air at normal atmospheric pressure surrounding an immediately created induction zone takes a finite time to rush in and replenish this void, as in blue region of p<1atm, in above figure. This doesn’t happen all of a sudden in zero time. Due to the delay, there exists an invisible transient boundary of the shape of the wing around the void, for the time period taken by the atmosphere to creep back into.
Therefore, air in the Induction-Zone constantly undergoes expansion within the invisible bounds of the imaginary conduit, until surrounding air refills the Induction-Zone.
That’s the mystery of Lift which has baffled scientists, laid bare right before your very own eyes 🙂
Its that simple folks 🙂 … but people went about wild goose chase in wind tunnels, and now computational fluid dynamics CFD, all the time completely missing the point that its the wing that moves like the vane of a vacuum pump, constantly creating and carrying its own low pressure zone, and stays aloft. There’s just no flow of any kind involved in creation of lift.
Read the ebook if you’re interested to learn more, there’s plenty to learn … 🙂
