AirFoil
Ever since the Homo Sapiens have gained undestanding, they have been taking inspiration from the Nature in all of their creations and Aircrafts are one of those creations too. In their attampt to fly like the birds, Humans created the Aircrafts . During the development stage of the aircrafts, there was one problem coming constantly in the way i.e., the lift. The aircraft needed to rise before it could take any flight and after the years of trials and researches, the answer was found in the form of "AirFoils" or "AeroFoils".
AirFoil is basically the shape of a wing, blade or sail which produces an aerodynamic force providing aircrafts enough lift to rise. There are two components of forces produced when an Airfoil is moved through a fluid. The component perpndicular to the direction of motion is called the "lift" while the parallel component is known as the "drag". The magnitude of these components depend upon the angle of attack and its orientation in the fluid.
Now, the point is what provides these airfoils tremendous amount to lift required to fly the tonnes of weight at incredible speeds. There are two arguments given for the explanation of the lift generation by these airfoils.
Bernoulli's Equal time argument
This is the most well-known argument given to explain the airfoils. It states that the two particles leaving at the attack point of the airfoil should meet at the same time at the end of airfoil. In order to fulfill this condition, the particle at the convex surface of theairfoil must travel at a higher speed compared to the particle at the other surface. And as the speed of the particle is higher at the above surface, the pressure decreases over there and due to this pressure difference, the lift force is generated which causes the aircrafts to rise.
But, the twist of the story is here.
There s no such law in physics which compells the two particles leaving at one end of the airfoil to meet again at the same time at the other end. They may never meet again and as this argument is the basis for the Bernoulli's explanation, it proves to be the wrong explanation.
Coanda Effect
The most considerable thing in this arument should be the reason which holds the fluid particles to remain stick to the curved surfaces instead of going staright. Every fluid particle tends to stick to the convex surfaces which is known as "Coanda Effect".
It is caused due to the curved streamline of the flow over the convex surfaces. The pressure over the convex surface is always greater than the pressure inside it. All the streamlines over the airfoil are curved with the curvature decreasing continuously while going away from the airfoil. At the enough distance from the airfoil, the pressure is equal to atmospheric pressure. This pressure difference is the reason for the lifit generation by the airfoil.
The above explanation does not states that the Bernoulli's equation is wrong but it's application to explain the airfoil is baseless. Nowadays, with the advancing technologies, more efficient airfoil design are coming with their applications extended from the aircrafts to the racing cars. The same principle which raises the aircrafts from the ground helps the spoilers of the high-speed cars to keep them sticked to the ground.
Image Source: Google
AirFoil is basically the shape of a wing, blade or sail which produces an aerodynamic force providing aircrafts enough lift to rise. There are two components of forces produced when an Airfoil is moved through a fluid. The component perpndicular to the direction of motion is called the "lift" while the parallel component is known as the "drag". The magnitude of these components depend upon the angle of attack and its orientation in the fluid.
Now, the point is what provides these airfoils tremendous amount to lift required to fly the tonnes of weight at incredible speeds. There are two arguments given for the explanation of the lift generation by these airfoils.
Bernoulli's Equal time argument
This is the most well-known argument given to explain the airfoils. It states that the two particles leaving at the attack point of the airfoil should meet at the same time at the end of airfoil. In order to fulfill this condition, the particle at the convex surface of theairfoil must travel at a higher speed compared to the particle at the other surface. And as the speed of the particle is higher at the above surface, the pressure decreases over there and due to this pressure difference, the lift force is generated which causes the aircrafts to rise.
But, the twist of the story is here.
Coanda Effect
The most considerable thing in this arument should be the reason which holds the fluid particles to remain stick to the curved surfaces instead of going staright. Every fluid particle tends to stick to the convex surfaces which is known as "Coanda Effect".
It is caused due to the curved streamline of the flow over the convex surfaces. The pressure over the convex surface is always greater than the pressure inside it. All the streamlines over the airfoil are curved with the curvature decreasing continuously while going away from the airfoil. At the enough distance from the airfoil, the pressure is equal to atmospheric pressure. This pressure difference is the reason for the lifit generation by the airfoil. The above explanation does not states that the Bernoulli's equation is wrong but it's application to explain the airfoil is baseless. Nowadays, with the advancing technologies, more efficient airfoil design are coming with their applications extended from the aircrafts to the racing cars. The same principle which raises the aircrafts from the ground helps the spoilers of the high-speed cars to keep them sticked to the ground.
Image Source: Google
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