gone under the hood of a solar race car,

去了太陽能賽車的引擎蓋下。

and explored battery technology in not one, but two episodes.

並對電池技術進行了探討，不是一集，而是兩集。

So now it's time to dig into an element of design

所以現在是時候挖掘設計的一個元素了

that's not just important to race cars,

這不僅對賽車很重要。

but every vehicle, or really anything and everything

但每輛車，或任何東西

that's designed and engineered.

那是設計和工程的。

I'm talking about aerodynamics.

我說的是空氣動力學。

In this chapter of our Learning Playlist,

在我們這一章的學習播放列表中。

we're asking, could today's solar race cars

我們要問的是，今天的太陽能賽車能不能做到？

drive us toward a more aerodynamic future?

推動我們走向更符合空氣動力學的未來？

Simply put, aerodynamics is the study

簡單地說，空氣動力學是研究

of how an object moves through the air.

物體在空氣中的運動方式。

But how do you engineer something to be aerodynamic?

但是，你怎麼能把一個東西設計成空氣動力學的？

Now if we take a plane design as an example...

現在我們以飛機設計為例... ...

Well, forgive me because I'm [CHUCKLES] not the best artist in the world.

嗯，原諒我，因為我不是世界上最好的藝術家。

But we have four forces of flight,

但我們有四種飛行的力量。

say that three times fast, to consider here.

說快三倍，要考慮這裡。

The first is weight.

首先是重量。

That is the downward force exerted on the object by gravity.

那就是重力對物體施加的向下的力。

The opposing force to that to that is lift.

與之相對應的是提升力。

That's the upward push,

這就是向上的推動力。

typically provided by the air underneath the moving object.

通常由運動物體下方的空氣提供。

Then there's thrust.

然後是推力。

That's the forward force that moves an object forward

這就是物體向前移動的前向力。

like, in the plane's case, the plane's engines.

像，在飛機的情況下，飛機的發動機。

And then finally, there's drag.

最後，還有就是拖。

and that goes in the opposite direction to thrust.

而這與推力的方向相反。

It's the force that resists an object's motion.

是抵抗物體運動的力量。

Now, whether we're talking about planes,

現在，我們是否在談論飛機。

spacecraft or solar race cars,

航天器或太陽能賽車。

the same four forces are always at play.

同樣的四種力量始終在發揮作用。

This is a 3-D printed model of Black Mamba,

這是黑曼巴的3D打印模型。

the Stanford Solar Car Project's solar racer

太陽車

for the 2019 World Solar Challenge.

為2019年世界太陽能挑戰賽。

When designing Black Mamba,

在設計黑曼巴時。

the Stanford team had to account for weight.

斯坦福大學隊必須要考慮到體重。

They wanted to keep the car as light as possible.

他們希望儘可能地保持汽車的輕量化。

And that's because, the lighter the car,

那是因為，車越輕。

the less force it takes to move the car.

移動汽車所需的力量越小。

Now, the real Black Mamba tips the scales

現在，真正的黑曼巴給了天平一個提示。

at roughly 180 kilograms.

大約在180公斤。

As far as cars go, that's really light.

就汽車而言，那真的很輕。

And traction and road grip are also crucial

而牽引力和路面抓地力也是至關重要的。

to maneuvering and winning races,

到操縱和贏得比賽。

because they can counteract lift.

因為它們可以抵消升降。

See, race cars are often so fast and so light,

你看，賽車往往是那麼快，那麼輕。

they're at risk of literally taking off.

他們有可能真的要起飛了。

So, using taller, wider tires,

所以，使用更高、更寬的輪胎。

and specially designed spoilers or wings

和特別設計的擾流板或機翼

that redirect the air around the vehicle

使車輛周圍的空氣重新定向

often factor into a race car's design

往往會影響到賽車的設計

to help the vehicle keep in contact with the road.

以幫助車輛與路面保持接觸。

Then we've got thrust.

那我們就有了推力。

And this one's pretty straightforward.

而這個很直接。

It's the power pushing the race car forward.

這是推動賽車前進的動力。

That's typically generated under the hood

這通常是在引擎蓋下產生的

by the car's engine.

由汽車的發動機。

Traditionally, with fossil fuel powered vehicles,

傳統上，以化石燃料為動力的車輛。

this power output is measured in horsepower.

這個動力輸出是以馬力為組織、部門的。

But with electric or battery powered vehicles,

但隨著電動車或電池動力車。

we can also think of it in terms of kilowatts,

我們也可以用千瓦來思考。

with one kilowatt equaling roughly 1.34 horsepower.

一千瓦約等於1.34馬力。

The real Black Mamba has an engine

真正的黑曼巴有一個引擎

powered by a 45 amp hour lithium-ion battery,

由45安時的鋰離子電池供電。

which is actually much smaller and less powerful

事實上，它的體積和功能都要小得多

than what something like a Tesla uses for its battery.

比像特斯拉這樣的電池使用的東西。

But because the car is so light,

但因為車子太輕了。

Black Mamba can top out at around 110 kilometers per hour.

黑曼巴最高時速可以達到110公里左右。

even with that battery.

即使是用那個電池。

And finally, there is drag.

最後，就是拖。

That's the resistance caused by air

那是空氣造成的阻力

pushing against a race car as it drives forward.

在賽車向前行駛的過程中，推著賽車。

Now, in order to calculate drag,

現在，為了計算阻力。

you multiply the drag coefficient

你乘以阻力系數

by the density of the air

由空氣密度

times half of the velocity squared

乘以速度平方的一半

times the object's frontal area.

乘以物體的正面面積。

Now, don't worry,

現在，不要擔心。

you'll probably never have to use this calculation

你可能永遠也用不上這個計算方法了。

unless you're a NASA or NASCAR engineer.

除非你是NASA或NASCAR的工程師。

This complex equation does give you a sense

這個複雜的方程確實給了你一個感覺

of how many factors are at play

有多少因素在起作用

when we talk about drag,

當我們談論拖。

including the all-important drag coefficient.

包括最重要的阻力系數。

The drag coefficient is the number we use

拖曳係數是我們使用的數字

to quantify the resistance

以量化阻力

that the object encounters when moving through a fluid.

物體在流體中運動時遇到的。

In this case, our object is our solar race car

在這種情況下，我們的對象是我們的太陽能賽車。

and our fluid is air.

而我們的液體是空氣。

Some other factors that affect drag coefficient

其他一些影響阻力系數的因素

include the object's shape and surface roughness

包括物體的形狀和表面粗糙度。

to reduce friction between the car and the air.

以減少汽車與空氣之間的摩擦。

If you watched our documentary series

如果您看過我們的系列紀錄片

on the 2019 World Solar Challenge,

在2019年世界太陽能挑戰賽上。

you may recall that teams

你可能還記得，球隊

like the one from Tokai University

像東海大學的那個

worked really hard

嘔心瀝血

to make their cars seamless and slippery.

以使他們的汽車無縫銜接，滑溜溜的。

In an effort to create a smooth flow of air

為了使空氣順暢地流動。

across their race car,

跨越他們的賽車。

some teams even use an innovative film wrap coating

有些團隊甚至使用了創新的薄膜包覆塗層。

called "shark skin" to better redirect air flow

稱為 "鯊魚皮"，以更好地引導空氣流動

and improve their car's aerodynamics.

並改善其汽車的空氣動力學。

Now, the concept of drag coefficient

現在，阻力系數的概念

can be a little bit abstract.

可以有點抽象。

So it might be useful to think of the drag coefficients

是以，我們可以把阻力系數看作是

of some everyday objects,

的一些日常用品。

like a brick.

像一塊磚頭。

A brick has a drag coefficient of about one.

一塊磚的阻力系數約為1。

Not very aerodynamic as you'd guess.

正如你所猜測的那樣，不是很符合空氣動力學。

In fact, the most aerodynamic shape that we know

事實上，我們所知道的最符合空氣動力學的形狀就是

is the teardrop

是水滴

with a drag coefficient of about 0.05

阻力系數約為0.05。

Think about some other objects, the...

想想其他的一些對象，該...

A 1996 Dodge Caravan

一輛1996年的道奇大篷車

has a drag coefficient of about 0.35.

具有約0.35的阻力系數。

MAREN: A brick with its blocky shape and its rough surface

MAREN：磚塊狀，表面粗糙。

encounters greater resistance

遇阻

when it's moving through the air

飄逸

than, say, a smooth aerodynamic teardrop.

比，說，一個光滑的空氣動力學水滴。

In the same way, a boxy minivan

同樣的，一輛箱式小貨車

encounters greater resistance

遇阻

than a sleek solar racer

比起光鮮亮麗的太陽能賽車

with a lower drag coefficient.

具有較低的阻力系數。

Now, the Stanford solar team

現在，斯坦福大學的太陽能團隊

wouldn't share Black Mamba's actual drag coefficient.

不會分享黑曼巴的實際阻力系數。

Yeah, so our team doesn't share some numbers

是啊，所以我們的團隊不分享一些數字。

just in our design.

就在我們的設計中。

It's mainly just the drag coefficient.

主要就是阻力系數。

It's kind of a long-standing thing

這是一種長期存在的事情。

within the solar teams.

太陽隊內。

I get it. I mean, in a race as competitive

我明白了 I get it.我的意思是，在一個競爭激烈的比賽中

as the World Solar Challenge,

作為世界太陽能挑戰賽。

letting the competition know

昭告天下

just how aerodynamic your car is

你的車有多符合空氣動力學

is, you know, probably not a good idea.

是，你知道，可能不是一個好主意。

But the Stanford team did confirm

但斯坦福大學的團隊確實確認

that their new racer is sleeker

他們的新賽車更時尚

and more aerodynamic than the past designs.

並且比過去的設計更符合空氣動力學。

So the driving design change that we had

所以，我們在設計上的驅動力變化是

was going with a single fairing bullet style aero body.

是要用單整流罩子彈式的航空體。

And that was the first time we ever tried doing

而這是我們第一次嘗試做的

a single fairing aero body.

一個單一的整流罩航空體。

We've always done, like, a multi-fairing car.

我們一直都在做，比如，多發車。

Usually that's a catamaran.

通常那是一艘雙體船。

MAREN: The multi-fairing design

MAREN：多發設計

has been widely used

已被廣泛使用

by many solar racers throughout the decades,

幾十年來，被許多太陽能賽車手。

including all of the winners of the World Solar Challenge

包括世界太陽能挑戰賽的所有獲獎者。

going all the way back to the very first race in 1987.

一直到1987年的第一場比賽。

And, spoiler alert,

而且，擾亂警報。

the winner of last year's race,

去年比賽的冠軍。

you guessed it, another multi-fairing catamaran design.

你猜對了，又是一個多舵雙體船的設計。

So why is a multi-fairing design so successful,

那麼，為什麼多發設計會如此成功。

even though it may not be

未必

as aerodynamic as the bullet design?

和子彈的設計一樣符合空氣動力學？

I think there is two main disadvantages to a bullet car.

我認為子彈車有兩大缺點。

In terms of stability, it improves the aerodynamics

在穩定性方面，它提高了空氣動力學性能。

if you have the wheels closer together.

如果你有輪子更接近。

but the trade-off to that

但這一代價

is as you move your wheels closer together,

是當你將車輪靠近時。

it's a lot easier to tip your car over.

這是很容易傾覆你的車。

The other problem is with the array size.

另一個問題是數組大小的問題。

MAREN: Compared to a sleeker, single fairing bullet car,

MAREN：與時尚的單整流罩子彈車相比。

the catamaran is wider

船大欺客

and it has more room to fit a larger solar array.

而且它有更多的空間來容納一個更大的太陽能陣列。

This ability to generate more energy

這種產生更多能量的能力

combined with greater stability

結合更穩定

tends to make for a winning combination.

往往會成為一個勝利的組合。

So while the bullet design does allow

所以，雖然子彈的設計確實讓

for a smoother air flow and improved drag,

使氣流更順暢，改善阻力。

which can translate into greater efficiency

這可以轉化為更高的效率

and potentially faster speeds,

和可能更快的速度。

it hasn't quite translated into taking home the trophy.

它還沒有完全轉化為拿回家的獎盃。

At least not yet.

至少現在還沒有。

Fun fact here. Many race cars, not just solar racers,

這裡有一個有趣的事實。很多賽車，不僅僅是太陽能賽車。

are actually designed

實際上是設計

to have a higher drag coefficient than minivans.

要比微型車的阻力系數高。

Yeah, that's right. Formula One designers

是的，這就對了 Formula One designers

deliberately increase drag

添堵

to help counteract upward lift

以幫助抵消上揚的作用

and improve traction and maneuverability.

並提高牽引力和機動性。

The Stanford Solar Car team plans to stick

斯坦福太陽能汽車團隊計劃堅持

with Black Mamba's sleek bullet design

採用黑曼巴的時尚子彈設計。

while continuing to improve

的同時，繼續改善

their solar racer's aerodynamics.

他們的太陽能賽車的空氣動力學。

And their goal is winning the next World Solar Challenge.

而他們的目標是贏得下一屆世界太陽能挑戰賽。

But the drive to innovate goes far beyond the next race.

但創新的動力遠不止於下一場比賽。

So, in the final chapter of our Learning Playlist,

所以，在我們學習播放列表的最後一章。

coming up next...

接下來...

Will solar cars really be a viable option

太陽能汽車真的會是一個可行的選擇嗎？

for all of us in the future?

為我們大家今後的?