Why can airplanes fly into the sky, and what is the principle?

Airplanes flew into the sky on Bernoulli's principle. This is called Bernoulli's principle.

Because the top of the wing is arc and the bottom is flat, when the aircraft is moving at high speed, the air flow above the plane is slower than that below, and the lower air plays a role in the wing, holding up the wing, so the plane can go to the sky.

An aircraft consists of five main parts: wings, fuselage, tail, landing gear, and power plant.

The main function of the wing is to provide lift for the aircraft to support the aircraft in the air, and also play a certain role in stabilization and maneuvering. Ailerons and flaps are generally installed on the wings. Manipulating the ailerons allows the aircraft to roll; Lowering the flaps increases the lift of the wings.

In addition, engines, landing gear, and fuel tanks can be installed on the wings. Wings come in a variety of shapes and in different numbers. In the early days when aviation technology was not developed, in order to provide greater lift, aircraft were mainly biplanes or even multiplanes, but modern aircraft are generally monoplanes.

Principle. In a real wing that generates lift, the airflow always converges at the trailing edge, otherwise there would be a point at which the airflow velocity is infinity at the trailing edge of the wing.

This condition is known as the Kuta condition, and only when this condition is met can the wing generate lift. In an ideal gas or at the beginning of the wing's movement, this condition is not satisfied, and a viscous boundary layer is not formed.

Usually the airfoil (wing cross-section) is longer than the lower distance, at the beginning of the absence of circulation, the upper and lower surface airflow velocity is the same, resulting in the lower airflow to the trailing edge when the upper airflow has not reached the trailing edge, the rear station is located at a point above the airfoil, the lower airflow must bypass the sharp trailing edge and meet the upper airflow.

Due to the viscosity of the fluid (i.e., the Conda effect), a low-pressure vortex is formed as the lower airflow wraps around the trailing edge, resulting in a large backpressure gradient at the trailing edge. Immediately, this vortex will be washed away by the incoming current, and this vortex is called the starting vortex.

According to Heimholtz's law of conservation of vortices, for an ideal incompressible fluid, there will also be an eddy around the airfoil in the opposite direction to the strength of the starting vortex under the action of force, which is called circulation, or circumferential circumference.

The circulation flows from the leading edge of the upper surface of the wing to the leading edge of the lower surface, so the addition of the circulation and the incoming flow causes the rear station to eventually move back to the trailing edge of the wing, thus satisfying the Kuta condition.

The amount of air around the wing caused by satisfying the Kuta condition causes the air flow on the upper surface of the wing to accelerate backwards, and the pressure difference can be deduced from Bernoulli's theorem and the lift force can be calculated, and the final lift generated by this ring can also be calculated by the Kuta-Zhukovsky equation: l (lift) = v (gas density, flow velocity, ring value), and the equation can also calculate the aerodynamic force of the Magnus effect.

According to Bernoulli's theorem – "The faster the velocity of a fluid, the smaller its static pressure (static pressure is the pressure generated by the fluid as it flows perpendicular to the direction of fluid motion). "Therefore, the pressure exerted by the air on the upper surface to the wing f1 is less than the pressure f2 on the lower surface.

The resultant force of f1 and f2 must be upward, which produces lift. The principle of lift is that the presence of the ring around the wing (attachment vortex) causes different flow velocities and different pressures on the upper and lower surfaces of the wings.

The invention of the airplane was the result of the development of bionics. Humans have long dreamed of flying in the air like birds. Through observation, it was found that birds do not fall when they spread their wings and glide in the air, and many scientists and flight enthusiasts invented the airplane after a long period of research and simulation.

Why do airplanes fly into the sky?

Among the many means of transportation, the most convenient, the most amazing is the airplane, many people think that the plane is very mysterious, weighing hundreds of tons of big guys, why can it easily fly, what is the principle of its ascent?

The main reason why the plane can fly into the sky is due to his ability to balance in the air with his memory.

The ascent of an airplane is based on Bernoulli's principle, which states that the greater the velocity of a fluid (including liquid and air), the lower its pressure; The smaller the flow velocity, the greater the pressure. When the aircraft flies, the streamline distribution of the air around the wing is different according to the shape of the cross-section of the wing, and the upper and lower streamlines are dense and the flow velocity is large, and the streamlines below are sparse and the flow velocity is small. From Bernoulli's equation, the pressure above the wing is small, and the pressure below is strong.

This creates a lift force in the direction acting on the wing. The greater the speed at which the aircraft travels, the greater the pressure difference, i.e., the lift. Therefore, the plane must take off at a high speed so that the plane can take to the sky.

Airplanes fly into the sky on the principle of aerodynamics. Most of the lift of the aircraft is generated by the wing, and the air flows to the leading edge of the wing, which is divided into two streams, upper and lower, which flow along the upper and lower surfaces of the wing respectively, and thus form a pressure difference, and the sum of the pressure difference perpendicular to the direction of the relative air flow is the lift of the wing. With the help of the lift gained from the wings, the heavier-than-air aircraft overcomes its own gravity due to the Earth's gravity and soars into the blue sky.

Airplanes fly into the sky on the principle of aerodynamics, the main of which are two fluid theorems: the continuity theorem and Bernoulli's theorem.

Most of the lift of the aircraft is generated by the wings, and the air flows to the leading edge of the wing, which is divided into two streams, upper and lower, which flow along the upper and lower surfaces of the wings respectively, and rejoin at the trailing edge of the wing and flow backwards. The upper surface of the wing is relatively convex and the flow tube is thinner, indicating that the flow rate is increased and the pressure is reduced.

On the lower surface of the wing, the air flow is blocked, the flow tube becomes thicker, the flow velocity slows down, and the pressure increases. As a result, there is a pressure difference between the upper and lower surfaces of the wing, and the sum of the pressure difference perpendicular to the direction of the relative airflow is the lift of the wing. With the help of the lift gained from the wings, the heavier-than-air aircraft overcomes its own gravity due to the Earth's gravity and soars into the blue sky.

The principle of airplanes, this is a matter for scientists. The principle of airplanes, this is a matter for scientists, we just need to do a good job of airplanes. It's good to be able to get to your destination.

The reason why the plane can fly is that it has forward momentum and upward lift.

The forward power is provided by the engine, which is well understood and needs no further explanation.

The upward lift is generated by the wings of the aircraft. The shape of the wing is a bit peculiar, with a relatively large upward arc on the upper surface and a flatter lower surface. When the aircraft glides forward under the impetus of power, the air flow rate flowing through the upper and lower surfaces of the wing is different, the upper is fast, the lower is slow, and the result is that the pressure on the upper and lower surfaces of the wing is different, the air pressure above is small, and the air pressure below is large, thus creating a pressure difference, and the entire wing produces an upward force, which is lift.

The faster the aircraft glides forward, the more lift the wings generate; When the lift force is greater than the gravitational force of the aircraft, the aircraft is lifted up, that is, it flies.

Pressure difference in a fluid.

The fluid that flows has a low pressure and is a fluid that is relatively stationary.

In the classic experiment, two sheets of paper separated in parallel blow towards the middle, and the paper will move closer to the middle.

Answer hello, the ascent of the aircraft is based on Bernoulli's principle, that is, the greater the flow velocity of the fluid (including air flow and water flow), the lower its pressure; The smaller the flow velocity, the greater the pressure. Let's take a look at the wing structure of an airplane. It turns out that the shape of the upper and lower sides of the wings of the aircraft is different, the upper side is more convex, and the lower side is flatter.

When an airplane taxi, the wings move in the air, which is equivalent to the air flowing along the wings in terms of relative motion. Because the shape of the upper and lower sides of the wing is different, the air on the upper side of the wing flows more distance than the air on the lower side (the curve is longer than the straight line) in the same amount of time, that is, the air on the upper side of the wing flows faster than the air on the lower side. According to the principle of hydrodynamics, when the aircraft slides, the air pressure on the upper side of the wing is less than that on the lower side, which causes the aircraft to produce an upward buoyant force.

When the plane taxith to a certain speed, this buoyancy reaches a force strong enough to make the plane fly. So, the plane went into the sky.

Why do airplanes fly into the sky?

In the past, when science and technology were not developed, people had the dream of flying to the sky, but now that the means of transportation have been developed, flying in the sky is no longer a dream, swimming in the water is not a problem, and even reaching outer space is not a myth. So why do airplanes fly? What is the principle of flight?

In fact, the airplane can fly, which is realized according to the principle of bird flight, that is, using air current. The principle that an airplane can fly lies in the structure of the upper wing and the lower wing to produce two air currents and fly; For ***, it mainly relies on his rotors, as well as its wings to sustain it.

Daniel Bernoulli proposed the "Bernoulli Principle" in 1726. This is the basic principle adopted by hydraulics before the establishment of the theoretical equations of continuum in fluid mechanics, the essence of which is the conservation of mechanical energy of fluids. Namely:

Kinetic energy + gravitational potential energy + pressure potential energy = constant. The most famous corollary is that when the flow is at a constant height, the flow velocity is high, and the pressure is small.

Bernoulli's principle is often expressed as p+1 2 v2 + gh=c, and this formula is called Bernoulli's equation. where p is the pressure at a point in the fluid, v is the velocity of the fluid at that point, is the density of the fluid, g is the acceleration due to gravity, h is the height at the point, and c is a constant. It can also be expressed as p1+1 2 v12+ gh1=p2+1 2 v22+ gh2.

It is important to note that since Bernoulli's equation is derived from the conservation of mechanical energy, it is only suitable for ideal fluids with negligible viscosity and non-compressibility.

It is important to know that the side section of the wing is a shape in which the upper edge is arched upwards and the lower edge is basically straight. Therefore, the air flow blows through the upper and lower surfaces of the wing and at the same time from the front end of the wing to the rear end, and the air flow from the upper edge is faster than the lower edge According to the Bernoulli equation of physics: the same fluid flowing through a certain surface has less pressure on the surface at a faster speed.

Therefore, it is concluded that the atmospheric pressure on the upper surface of the wing is smaller than that on the lower surface, so that the lift force is generated, and the lift force reaches a certain level, and the aircraft can lift off the ground.

It was Hercules who threw the plane into the sky.

Airplanes are heavier-than-air aircraft, so they need to expend their own power to gain lift. And the ** of lift is the effect of air on the wing in flight.

The upper surface of the wing is curved and the lower surface is flat, so when the wing is in relative motion to the air, the air flowing through the upper surface travels a distance (s1) in the same time (t) than the air flowing through the lower surface (s2), so the relative velocity of the air on the upper surface is faster than the air on the lower surface (v1 = s1 t> v2 = s2 t1). According to Panulli's theorem – "The pressure exerted by a fluid on the surrounding matter is inversely proportional to the relative velocity of the fluid." "Therefore, the pressure exerted by the air on the upper surface to the wing f1 is less than the pressure f2 on the lower surface.

The resultant force of f1 and f2 must be upward, which produces lift.

From the principle of the wing, we can also understand how the propeller works. The propeller is like a vertical wing, with the bump facing forward and the smooth facing backward. The resultant force of the pressure as it rotates forward, pushing the propeller forward, thus driving the aircraft forward.

Of course, the propeller is not simply raised and smooth, but has a complex curved surface structure. Older propellers were fixed shapes, while later designs were designed with relative angles that could be changed to improve propeller performance.

Flying requires power to move the aircraft forward, and more importantly, for the aircraft to gain lift. Early airplanes were usually powered by piston engines, and four-stroke piston engines were the mainstay. The principle of this type of engine is shown in the figure, which is mainly to inhale air, mix it with fuel, ignite and expand, drive the piston to reciprocate, and then convert it into the rotary output of the drive shaft.

The power emitted by a single piston engine is very limited, so several piston engines are connected in parallel to form a star or V-piston engine.

Most modern high-speed aircraft use jet engines, the principle is to draw air, mix it with fuel, ignite, ** the expanded air is sprayed backwards, and its reaction force pushes the aircraft forward. Compressor fans draw air from the air intake, and compressed air is compressed one by one, so that the air can better participate in the combustion. The orange-red cavity behind the fan is the combustion chamber, where a mixture of air and oil is ignited, and the combustion expansion is ejected backwards, pushing the last two fans to rotate and finally vent out of the engine.

The last two fans are mounted on the same central shaft as the front compressor fan, so they drive the compressor fan to continue to draw in air, thus completing a working cycle.

Airplanes fly into the sky with the lift produced by their wings.

The aircraft takes off by the thrust of the engine to generate speed, and the speed generates lift through the shape change of the wings, the thrust is greater than the drag, and the lift is greater than the gravity, so that the aircraft can take off and climb high. When the aircraft climbs to the cruising altitude, the small throttle is closed, which is called level flight, at this time, the lift is equal to gravity, and the thrust is equal to the drag, that is, the constant speed flight.

When the wing is parallel to the direction of the airflow, the velocity is greater than the velocity in front of the wing due to the small cross-sectional area of the airflow above the wing, while the air flows horizontally under the wing, so the velocity under the wing is roughly equal to the velocity in front. We already know that when a fluid flows, the pressure is low where the flow velocity is high, and the pressure is strong where the flow velocity is small. It can be inferred that the pressure under the wing is stronger than the pressure above the wing, so that the upward force acting on the wing is generated, and this force is called lifting or lift.

The problem of wing lift is precisely "the flow velocity of the fluid is large, and the pressure is small; The flow rate is small, the pressure is strong". If the leading edge of the wing is slightly upward, at a small elevation angle with the direction of the airflow, the pressure difference between the upper and lower parts of the wing is greater than when the wing is parallel to the direction of the airflow, and the lifting force generated is relatively large. When the lifting force is greater than the gravitational force of the aircraft, the aircraft rises.

Does the plane have to take off against the wind?

Of course not"Definitely"Hoo! The plane can take off against the wind and downwind!

According to the theory of flight, the advantages of aircraft taking off against the wind are:

1.Increase the indicated airspeed of the aircraft, so that the aircraft reaches the normal take-off speed in advance (which is equivalent to delaying the stall timing of the aircraft and increasing the steering performance of the aircraft).

2.Shorten the runway length required for take-off and allow the aircraft to fly off the ground earlier (which is equivalent to reducing the wear and tear of tires and parts).

3.In the unlikely event that the aircraft abandons take-off on the runway for any reason, the headwind helps the aircraft to slow down and stop and there is also a longer remaining runway available.