Bernoulli and Newton - What is Lift and Drag: A short review

What is Bernoulli's explanation for a lift?

The design of an airplane's wing contributes to lift. The air moves faster over the curved upper surface of the wing than it does under the flat surface of the wing. The wing lifts toward the area of low pressure because the faster flowing air produces less pressure than the slower moving air.

How does Newton explain lift?

Newton's third law of motion states that, for every action, there is an equal and opposite reaction. Based on this law, wings are forced upwards because they are tilted, pushing air downwards so the wings get pushed upwards.

 What is Lift?

The force that keeps an aeroplane in the air is known as lift. Lift is the force that keeps an aeroplane in the air by directly opposing its own weight. Every portion of the aeroplane generates lift, but the wings create the majority of it on a typical airliner. The velocity of the aeroplane through the air produces lift, which is a mechanical aerodynamic force. Lift is a vector quantity with both a magnitude and a direction associated with it because it is a force. Lift is oriented perpendicular to the flow direction and acts through the object's centre of pressure. The magnitude of lift is influenced by a number of things.

When a solid object turns a flowing gas flow, lift occurs. According to Newton's Third Law of action and reaction, the flow is turned in one direction while the lift is generated in the opposite direction. Because air is a gas with free-moving molecules, any solid surface can deflect a flow. Both the upper and lower surfaces of an aircraft wing contribute to flow turning. An inaccurate explanation of lift results from ignoring the role of the upper surface in twisting the flow.

What is Drag?

The Drag is the aerodynamic force opposing an aircraft's motion through the air. Every aspect of the plane (including the engines!) generates drag. What causes drag to happen?

A mechanical force is drag. The interaction and contact of a solid body with a fluid produces it (liquid or gas). The solid body must be in contact with the fluid to cause drag. 

There is no drag if there is no fluid. The differential in velocity between the solid item and the fluid causes drag. Between the item and the fluid, there must be movement. There is no drag if there is no movement.

What does Drag do?

Without making the post too complex in simple short, the drag is the aerodynamic resistance to an object's motion through a fluid. Form drag is a type of drag that is caused by the shape of the aircraft. The local velocity and pressure change as air flows around a body. A variable pressure distribution will produce a force on the body because pressure is a measure of the momentum of the gas molecules, and a change in momentum produces a force. The drag component of the aerodynamic force is perpendicular to the motion, while the lift component is perpendicular to the motion. Both the lift and drag forces act on the object's centre of pressure.

Bernoulli vs Newton

For many years, theories on the generation of lift have been a cause of significant debate and intense debate.

The views are divided between two camps. One group accept the "Bernoulli" stance that lift is generated by a pressure difference across the wing, and the other group support the "Newton" position that lift is the reaction force on a body induced by deflecting a flow of gas, usually fall into two groups.

It's worth noting that neither Newton nor Bernoulli ever tried to explain how an object's aerodynamic lift works.

Which side is right? How is lift produced?

When a gas flows over or through an object, the molecules of the gas are free to move about the object; unlike in a solid, they are not tightly bonded to one another. The gas has a velocity connected with it because the molecules move. At different points near the object, the velocity within the gas might have extremely varied values. Bernoulli's equation connects the pressure in a gas to the local velocity; as the velocity around an object varies, so does the pressure. The aerodynamic force on the body is calculated by multiplying the pressure variation by the area around the entire body.

The aerodynamic force on the body is calculated by multiplying the pressure variation by the area around the entire body. The component of the aerodynamic force that is perpendicular to the gas's original flow direction is known as lift. The drag component of the aerodynamic force is the component of the force that is parallel to the gas's original flow direction. The aerodynamic force is now calculated by adding up the velocity variations around the object rather than the pressure variations. The net twisting of the gas flow is caused by the integrated velocity variation around the item.

The clash begins here

What is the argument?

Arguments arise because people mis-apply Bernoulli and Newton's equations and because they over-simplify the description of the problem of aerodynamic lift. The most popular incorrect theory of lift arises from a mis-application of Bernoulli's equation.

The following is the truth:

A twisting action of the flow will result in a re-action (aerodynamic force) on the item, according to Newton's third law of motion. As a result, "Bernoulli" and "Newton" are both correct. The aerodynamic force on an object is calculated by combining the effects of pressure and velocity. We can determine the amount and direction of the aerodynamic force using equations developed by each of them..

We must conserve mass, momentum, and energy in the flow of a gas at the same time. The conservation of momentum is the subject of Newton's laws of motion. Bernoulli's equation is derived from the principle of energy conservation. In the generation of lift, both of these equations are satisfied; both are correct.

Credit: Google