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快!上飞机再解释

How do Airplanes fly?

近代的飞机是真正意义上的工程奇迹
Modern airplanes are truly engineering marvels.
它们要在空中克服高度紊流且不可预测的气流
They overcome highly turbulent and unpredictable currents in the air,
并且通过运行许多复杂的机制来完成飞行
and complete their flights by undertaking many complex maneuvers.
你可曾想过飞行员是如何做到这一点的?
Have you ever thought of how the pilots are able to achieve this?
或者当飞行员操作某些控制器时飞机会怎样?
Or what happens to the airplane when the pilot operates certain controls?
在本视频中 我们将探索一架飞机是如何飞行的
In this video, we will explore how an airplane flies,
以及飞行员如何用符合逻辑而又简单的方法来控制飞机
and how pilots are able to control an airplane in a logical yet simple way.
特此鸣谢SimScale提供计算流体动力学支持
We thank SimScale for lending their CFD support
从而使本视频信息更加丰富
and making this video more informative.
首先 让我们近距离看一下现代飞机的机翼和尾翼
First, let’s have a closer look at modern airplanes’ wings and tails.
你会注意到一个有趣的地方
One interesting thing you will notice is that
它们没有被做成一个固定整体
they are not made as a single solid piece.
飞机的机翼和尾翼有许多可移动的部分
The wings and tails of the airplanes have many movable parts.
在整个机翼与其不同的部件中最吸引人的是
The most fascinating thing about the whole wing and the different parts of it
它们组成了一个流体力学中非常特殊的形状
is that they form a very special shape in fluid mechanics.
那就是机翼形状
That is the airfoil shape.
仅仅通过理解这个简单形状背后的物理现象
Just by understanding the physics behind this simple shape
就能让你彻底理解飞机的物理原理
will allow you to completely understand airplane physics.
让我们对机翼了解更多吧
Let’s learn more about airfoils.
机翼与空气相对移动时产生一个升力
An airfoil produces a lift force when moved relative to the air.
这个升力使得一架飞机在空中飞行
This lift force makes an airplane fly.
这个升力是如何产生的呢
How is this lift produced?
机翼产生如图所示的一个下冲气流
The airfoil produces a down wash as shown.
这就导致机翼顶部和底部产生压力差
This causes a pressure difference at the top and bottom of the airfoil,
因此产生升力
and hence produces lift.
SimScale进行高效的流体力学分析
This high-quality CFD analysis, using SimScale software,
能够清晰地阐明这个现象
clearly illustrates this fact.
通常 越大的迎角
Generally, the higher the angle of attack,
对应越大的下冲气流和升力
the greater will be the down wash, and therefore the lift force.
一个较大的空速也可以显著地增大升力
A greater airspeed also increases the lift force significantly.
有趣的是 在人类首次成功试飞中
Interestingly, in mankind’s first successful flight,
莱特飞行器也使用了相同的机翼原理
the Wright Flyer also made use of this same airfoil principle.
虽然他们的机翼只是一个简单的弯曲形状
Even though their airfoils were a simple curved shape,
但也足以产生一个很好下冲力
it was sufficient to produce a good down wash.
更明确地说 他们的飞机有上下两个这样的机翼
More specifically, their airplane had two such airfoils.
增加升力的另一个方法
One more idea to increase the lift force
是把机翼形状转变成这样
is by altering the airfoil shape like this.
形状的改变肯定会增加下冲力和机翼面积
The alteration in shape will definitely increase the down wash and the wing area,
从而提供更大的升力
hence giving greater lift.
总的来说 有三种方法来增加机翼的升力
In short, there are three techniques to increase the lift of an airfoil.
让我们把这种机翼型知识运用到飞机上
Let’s apply this airfoil knowledge to the airplane.
如果我们启动后缘襟翼和前缘缝翼
If we activate the flaps and slats,
就能增加下冲力和升力
it increases the down wash and increases the lift.
副翼可以上下翻动
The ailerons can move up and down, and for that reason,
因此能够分别减小和增大升力
the lift force can decrease and increase respectively.
在飞机的尾部 你可以看见两个可活动翼面
At the tail of the airplane, you can see two attachments:
分别是飞机的方向舵和升降舵
the rudder and the elevators.
通过调整升降舵 你能够控制尾部的垂直力
By adjusting the elevators, you can control the vertical force on the tail.
而通过调整方向舵 你能控制水平力
By adjusting the rudder, you can control the horizontal force.
现在 让我们进入本视频最有趣的部分
Now, let’s get into the most interesting part of the video:
即通过使用这些简单的活动翼面来控制飞机
controlling the aircraft using these simple wing attachments.
让我们从飞行中的起飞部分开始吧
Let’s start with the “take-off” part of the flight.
为了让飞机从地面起飞
To get the airplane to take off from the ground,
你要做的就是用多种方式来增加升力
what you have to do is increase the lift force using various techniques
并且确保升力大于重力
and make sure that this force is more than the gravitational pull.
飞行员需要一起使用以下3种增加升力的方法来使飞机顺利起飞
Pilots apply all of the 3 lift-increased techniques together for a successful take-off.
首先 通过增加引擎推力来使飞机加速
First, the speed of the airplane is increased by increasing the thrust of the engines.
当飞机的速度足够快时
When the airplane’s speed is high enough,
飞行员就会启动后缘襟翼和前缘缝翼
the pilots activate the flaps and slats.
由此进一步增大升力
Lift is further increased due to this.
当飞机准备起飞时 他们将升降舵向上翻
When the airplane is ready for take-off, they activate the elevators upwards.
产生的尾部垂直力使飞机如视频中那样翘起
The tail force tilts the airplane as shown,
由此机翼的迎角将会增大
and the angle of attack of the airfoil will be increased.
升力由此突然增大 然后飞机就起飞了
The lift is suddenly increased due to this, and the airplane takes off.
通常 起飞过程中需要一直维持15度的迎角
Usually, an angle of attack of 15 degrees is maintained for the take-off.
在之前的讨论中 我们谈到了引擎的推力
In all these discussions, we’re talking about the engine’s thrust.
但是引擎是如何产生推力的?
But how is the engine able to generate thrust?
为此近代飞机使用一种
Modern airplanes use special kinds of engines
名为涡轮风扇发动机的特殊引擎
called “turbofan engines” for this purpose.
该引擎内风扇的反作用和排出废气的反作用力
In this, the fan’s reaction and the reaction force of the exhaust
为飞机提供了必要的推动力
give the necessary thrust force.
通过燃烧更多的燃料 飞行员就能获得更强的推力
By burning more fuel, the pilot can achieve more thrust.
飞机的燃料储存在两个机翼里面
The fuel of an airplane is stored inside the wings.
飞机起飞完成后便是飞机爬升的阶段
After the take-off, next comes the climb phase of the aircraft.
只要引擎的推力大于所受阻力
As long as the engine’s thrust is more than the drag,
飞机的速度将会持续增大
the speed of the airplane will keep on increasing.
速度越大 升力越大
The greater the speed, the higher will be the lift force.
这样就使得飞机上升
This will cause the airplane to go up.
当飞机达到预定飞行高度
When the airplane reaches level flight,
它便停止加速且保持高度
there won’t be any acceleration or change in altitude.
这一点你可以通过以下情况看出
You can see that with this condition:
推力大小应与所受阻力完全相等
the thrust should be exactly equal to the drag,
同时升力应与飞机所受重力完全相等
and the lift should be exactly equal to the weight of the airplane.
现在 让我们来讨论一下最重要的部分
Now, let’s discuss the most crucial part:
飞机是如何转向的呢?
how does an airplane change direction?
你也许认为调整飞机方向舵就行了 这你也能做到
You might think that just by adjusting the rudder, you would be able to do this.
方向舵产生一个水平力
The rudder produces a horizontal force.
并且这个力能使飞机转向
And this force can turn the airplane.
然而 这种直接改变方向的方式将导致乘客不适
However, such a direct change in direction will cause discomfort to passengers
并且这是不切实际的方式
and it is not a practical method.
像视频中那样转弯 你还需要一个离心力
To make a turn as shown, what you need is a centrifugal force.
让我们来看一下飞行员是如何实现这个离心力的
Let’s see how pilots achieve this centrifugal force.
飞行员仅使一个副翼上翻 另一个副翼下翻
Pilots just make one aileron go up and the other aileron go down.
两翼升力的不同会使得飞机横滚
The difference in the lift force will make the airplane roll.
在这种横滚情况下 升力并不是垂直的
In this roll condition, the lift is not vertical.
升力的水平分力可提供所需的离心力
The horizontal component of the lift can provide the necessary centrifugal force
让飞机倾斜转弯
to bank the aircraft.
如此 飞行员就能让飞机在任意半径下转弯
In this way, the pilot can make a turn of any radius
这取决于横滚的角度和飞机的速度
depending upon the angle of roll and the speed of the airplane.
然而 这种倾斜的方式还是有一些缺陷的
However, this banking technique has some drawbacks.
当你保持一边副翼上翻而另一边下翻时
When you keep one aileron up and the other aileron down,
两侧机翼上所受的阻力是不一样的
the drag forces induced on the wings are not the same.
这会导致飞机偏航
This will cause the airplane to yaw.
这种现象称为反向偏航
This phenomenon is known as adverse yaw.
需要同时操作方向舵来防止反向偏航
The rudder has to be operated simultaneously to prevent the adverse yaw.
飞行员控制不同活动翼面
The way pilots control the different wing attachments
和整个飞机的方式已经在本动画中阐明
and the whole airplane is illustrated in this animation.
实际上只要通过一台使用电传系统的中控计算机
In practice, a control computer accurately manages all these wing attachments
就能精确控制所有活动翼面
using a fly-by-wire system.
飞行员通过减小引擎的推力
To descend the airplane, what pilots do is decrease the engine’s thrust
和保持机头向下来使飞机降落
and keep the nose of the airplane down.
你会发现这与爬升操作完全相反
You can see this is exactly the opposite of the climb operation.
随着飞机速度减小 飞机准备着陆
As the airplane loses speed, it gets ready for landing.
在这个阶段 后缘襟翼和前缘缝翼再次启动
At this stage, the flaps and slats are activated again.
这些活动翼面同样增大了阻力
These devices also increase the drag.
为了增大阻力 一种名为扰流板的活动翼面也将启动
To increase the drag further, a wing attachment called “the spoiler” is also activated.
飞行员还有一个用来缩短停止所用距离的窍门
The pilots use one more trick here to reduce the stopping distance,
那就是反向推力
which is reverse thrust.
此时引擎盖大大敞开着
Here, the engine covers open wide,
而本来是向后走的空气却被强制向前
and the air which was supposed to go backwards is forcefully directed forwards.
这样就明显地产生了反向推力
This will obviously generate reverse thrust,
从而会让飞机的停止容易些
and will make the stopping of the airplane easier.
我们在本视频中看到的CFD模拟视频是由SimScale出品的
The CFD simulations we saw in this video were produced by SimScale,
它是一款强大的基于云计算FEA和CFD的软件
a powerful cloud computing-based FEA and CFD software.
仅使用你的普通笔记本电脑或个人电脑就能进行复杂的CFD分析
To perform complex CFD analyses using your normal laptop or PC,
只要在SimScale.com网站上建立一个免费社区账户就能开始探索了
just create a free community account at SimScale.com, and explore.
请查看视频简介
Please check the description.
谢谢
Thank you.

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译制信息
视频概述

本视频通过直观的动画方式介绍了飞机起飞 ,降落及转向的原理,以后坐飞机时可以吹牛啦

听录译者

Bingo

翻译译者

陈光

审核员

审核员_Y

视频来源

https://www.youtube.com/watch?v=F077WDnB8P8

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