慢動作下的消音器紋影衝擊波 - 每天變聰明一點點 204：英語精讀講義

A quick caveat before we get started here. 表達脈絡

在我們開始之前，我先簡單聲明一下。

I do not want Smarter Every Day to be observed 語氣意圖

我不希望 Smarter Every Day 被看作是

as a channel that glorifies weaponry.

一個吹捧武器的頻道。

I am just fascinated by fluid dynamics, ballistics, 文法

我只是對流體力學、彈道學、

optics,

光學、

uh mechanics, aerodynamics,

呃，力學、空氣動力學很著迷，

all this stuff is just fascinating to me.

所有這些東西都讓我非常著迷。

And I am hard pressed to find one singular thing that I can study 慣用語

此外，我很難找到任何其他單一的研究對象，

that wraps all these physical phenomena into like the perfect Venn diagram 文化背景

能夠把所有這些物理現象像一個完美的文氏圖一樣結合在一起，

that tickles my brain 慣用語

讓我感到如此絞盡腦汁、

quite like firearms.

又像槍械這樣有趣的。

So that's why you will see me studying firearms so often.

所以這就是為什麼你們經常看到我研究槍械。

And um I hope you realize that I'm doing it

而且嗯，我希望你們能意識到我正在盡可能

as intelligently and respectfully as I can. 文法

理智並且充滿敬意地做這件事。

That being said, 表達脈絡

話雖如此，

I've made some observations in the last episode 片語搭配

我在上一集做了一些觀察，

and I've learned some stuff.

並且學到了一些東西。

And I've also decided to push a little bit further 慣用語

而我也決定再深入一點，

by studying suppressors.

來研究一下減音器。

So let's look at this

所以讓我們來看看這個，

and try to get smarter every day.

並且努力每天變聰明一點（Smarter Every Day）。

First, let's revisit what we learned in the last episode. 表達脈絡

首先，讓我們回顧一下我們在上一集學到的內容。

Using a Phantom camera with a clever photography technique called schlieren, 用詞

使用一台 Phantom 攝影機，以及一種叫做紋影（schlieren）的巧妙攝影技術，

which is German for streak,

這在德語裡是條紋的意思，

by the way,

順帶一提，

we observed that the supersonic bullet creates an angular shock cone

我們觀察到超音速子彈會產生一個有角度的震波錐，

and the angle of that cone can be used to determine the Mach number. 講解

而這個錐體的角度可以用來決定馬赫數。

We also learned from Dr. Konigstrasse at UAH

我們也從 UAH 的 Konigstrasse 博士那裡學到，

that a bullet traveling in the transonic regime can create supersonic flow around it 用詞

在穿音速區域飛行的子彈可以在其周圍產生超音速氣流，

because the air has to speed up 片語動詞

因為空氣必須加速

and rush around the outside of the surface of the bullet.

並衝過子彈表面的外圍。

This is a connection I didn't make at the time, 片語搭配

這是我當時沒有聯繫起來的一點，

but we've all seen these awesome pictures of like a fighter jet

但我們都見過那種戰鬥機的炫酷照片，

with this cone of vapor behind it.

它的後面跟著這樣一個蒸氣錐。

This is totally why that happens.

這完全就是它發生的原因。

The jet is flying along in the transonic regime,

噴射機是在穿音速區域飛行的，

just like that bullet.

就像那顆子彈一樣。

And just like the normal shock wave that occurs on the side of the subsonic bullet,

就像次音速子彈側面發生的正常震波一樣，

that's happening on the jet.

這種現象也在噴射機上發生。

And it does two things. 表達脈絡

它導致了兩件事。

Number one,

第一，

it makes this cone of vapor form on the jet.

它讓這個蒸氣錐在噴射機上形成。

And number two,

第二，

it makes me all tingly inside.

它讓我內心一陣激動。

Okay, so I think we have a good understanding at this point

好的，我認為我們現在對

of shock waves created by a bullet itself.

子彈自身產生的震波有了很好的了解。

You may have heard someone talk about the crack of a bullet as it passes. 用詞

你可能聽人談論過子彈飛過時的爆裂聲。

That's created by this shock wave.

那就是由這種震波產生的。

But if you think about the bang of a gunshot,

但是如果你想想槍聲的轟鳴聲，

like it's all those rapidly expanding gases out the front of a muzzle, right?

比如槍口前面所有快速膨脹的氣體，對吧？

So it's time to hone in on that area right there 片語動詞

所以現在是時候集中注意力在那個區域上，

and study that with super slow super slow mo suppressor schlieren.

用超慢速、超慢速減音器紋影攝影來研究它了。

There you go.

終於唸出來了。

It's hard to say. 慣用語

這話真難唸。

In a past episode of Smarter Every Day,

在 Smarter Every Day 的往期節目中，

I asked a company to fabricate a see-through suppressor 用詞

我請一家公司製造了一個透明的減音器，

so we could see the flame front propagate through the baffles

這樣我們就能看到火焰前鋒在擋板中傳播，

and try to understand what was going on. 片語動詞

試著了解到底發生了什麼事。

That was effective in showing what happens on the inside of their particular suppressor design,

這有效地展示了他們特定減音器設計內部發生的事情，

but what I want to see is exactly what happens on the outside of the suppressor.

但我想要看的是減音器外部到底發生了什麼。

After all, that's where all the noise is. 表達脈絡

畢竟，所有的噪音都在那裡。

Here's my friend Coop firing his rifle chambered in 300 Blackout, 用詞

這是我的朋友 Coop 在用他的 300 Blackout 口徑步槍開火，

both suppressed and unsuppressed. 用詞

包括裝減音器和不裝減音器兩種情況。

I'm going to show you a full minute of slow motion video

我要給你們看整整一分鐘的慢動作影片，

because I believe it does the best job of explaining the physics of what's going on. 片語搭配

因為我相信它最能解釋發生這些情況的物理原理。

On the left, we have a suppressed weapon,

在左邊，我們有一把裝了減音器的武器，

and on the right, we have the same weapon unsuppressed.

而在右邊，我們有同一把沒裝減音器的武器。

When they're first fired,

當它們剛開火時，

you can see straight away that the weapon on the right seems to have a larger,

你可以立刻看到右邊的武器似乎有更大、

dirtier blast.

雜質更多的爆炸。

But after 4 milliseconds,

但是在 4 毫秒之後，

there doesn't seem to be any more shock waves. 文法

似乎就沒有更多的震波了。

We're just venting the exhaust gases at that point.

那個時候我們只是在排出廢氣。

The weapon on the left, however, is still chugging away. 片語動詞

然而，左邊的武器還在繼續「噴吐」。

It's like this initial blast has been bouncing around on the inside of the suppressor

就像是這種最初的爆炸一直在減音器內部來回反彈，

and just a little bit of the gases are being leaked out with every reverberation.

然後每次殘響都只有一點點氣體洩漏出來。

Watch what happens next, though.

不過，請看接下來發生了什麼事。

On the right,

在右邊，

the echo from the unsuppressed weapon is huge and very distinct.

沒裝減音器武器的回聲巨大且非常清晰。

You can see how powerful and singular that initial blast was 文法

你可以看出最初的爆炸是多麼強大和集中，

by how sharp the echo is when it returns.

因為它返回時的回聲非常尖銳。

Imagine that echo entering your ears. 文法

想像一下那回聲進入你的耳朵。

Meanwhile, you can still see that the suppressed weapon is dissipating that acoustic energy slowly.

同時，你仍然可以看到裝了減音器的武器在緩慢耗散聲能。

This is like the clearest example I can show of that energy being dissipated differently.

這可能是我能展示的這種能量被不同方式耗散的最清晰的例子了。

On the right, the unsuppressed version,

在右邊，不裝減音器的版本，

the whole thing's over in like a millisecond and a half. 文法

整個過程大概一毫秒半就結束了。

But on the left,

但在左邊，

the same acoustic energy is dissipated over 15 milliseconds.

同樣的聲能被耗散了超過 15 毫秒。

That is a direct comparison showing you

這是一個直接的對比，向你展示

that it almost acts like a capacitor in a circuit. 表達脈絡

它幾乎就像電路裡的電容器一樣起作用。

It's like slowly filtering the energy as it exits.

就像在它退出時慢慢過濾能量。

Anyway, that energy dissipation does not come for free. 慣用語

無論如何，這種能量的耗散是有代價的。

Suppressors heat up very, very quickly.

減音器升溫非常、非常快。

All that thermal energy is captured because it doesn't dissipate away from the weapon.

所有的熱能都被捕獲了，因為它沒有從武器上散去。

So the problem with suppressors is if you fire enough rounds through them, 用詞

所以減音器的問題是，如果你透過它們發射了足夠多的子彈，

they heat up very, very fast

它們升溫非常非常快，

and they can cause malfunctions and even damage to the weapon.

可能會導致故障，甚至損壞武器。

Now let's look at subsonic ammunition being fired from a suppressor.

現在讓我們看看從減音器發射的次音速彈藥。

This is absolutely fascinating.

這絕對令人著迷。

Okay, first observation.

好的，第一個觀察結果。

The first thing that leaves the suppressor is unburnt powder. 用詞

離開減音器的第一樣東西是未燃燒的火藥。

And look at that.

看看那個。

There's little baby shock waves. 用詞

有微小的震波。

They're supersonic.

它們是超音速的。

Now whether this is gunk coming loose from previous shots or whatever, 片語搭配

現在，這是不是之前射擊鬆動的汙垢或者其他的什麼，

I don't know.

我不知道。

But it's clearly supersonic.

但它顯然是超音速的。

Second, did you see that little vortex ring poot out the end? 用詞

第二，你看到末端噴出那個小渦環了嗎？

Okay, here we go.

好的，開始吧。

Bullet time. 文化背景

子彈時間。

We know this is a subsonic round,

我們知道這是一種次音速彈，

so we're expecting normal shock waves on the sides of the bullet.

所以我們預期子彈側面會有正常的震波。

But look at that.

但看看那個。

They're not there until the bullet is several inches away from the muzzle. 文法

直到子彈距離槍口幾英吋的時候它們才出現。

It is crazy to think about how complicated this flow environment is,

想到這種流動環境有多複雜就很瘋狂，

but it's really fun to make these observations and try to figure it out. 片語動詞

但是做這些觀察並試著弄清楚真的很有趣。

What are these little squirrely things that come out of the suppressor? 用詞

從減音器裡出來的這些奇形怪狀的小東西是什麼？

Okay, so what you're seeing here on this Blackout cartridge is

好的，關於這種 Blackout 子彈你在這裡看到的是

you're seeing unburnt propellant leaving the muzzle before the bullet does. 文法

你看到未燃燒的推進劑比子彈先離開槍口。

And so for 300 Blackout,

所以對於 300 Blackout 來說，

optimally you get complete burnout around 9 and a half to 10 inches of barrel length. 用詞

最理想的情況是在 9.5 到 10 英吋的槍管長度時完全燃燒。

And so this is a 10.2 inch barrel length.

而這是一個 10.2 英吋長的槍管。

And so we're right on the threshold of burning all the propellant out before the bullet leaves the muzzle. 片語搭配

所以我們剛好處於子彈離開槍口前燒光所有推進劑的臨界點。

Well, look, there was a supersonic piece of powder.

嗯，看，有一塊超音速的火藥。

See that?

看到了嗎？

Woah.

哇喔。

This is insane.

這太瘋狂了。

We're just like learning like important stuff. 用詞

我們感覺就像是在學習重要知識一樣。

All right.

好的。

Well, that was delightful.

剛才真是太開心了。

What did we learn, John?

約翰，我們學到了什麼？

Propellant outruns bullets sometimes. 用詞

推進劑有時候跑得比子彈快。

You may have grains of propellant that exit the muzzle faster than the bullet supersonically.

你可能會有顆粒狀的推進劑以超音速比子彈更快地退出槍口。

That's crazy.

太瘋狂了。

And there's a shock wave on those grains of propellant.

而且這些推進劑顆粒上還有震波。

Exactly.

完全正確。

That's uh I never would have thought that. 文法

那個，呃，我從來沒想過。

Neither would I. 文法

我也沒想過。

I hope this episode earned your subscription. 語氣意圖

我希望這一集能贏得你的訂閱。

You can also click the bell to be notified anytime I upload something

你也可以點擊小鈴鐺，這樣我每次上傳影片你都會收到通知，

or not. 語氣意圖

或者不點。

Whatever.

無所謂啦。

You're a smart person.

你是個聰明人。

You can make your own decisions.

你能自己做決定。

I'm Destin, you're getting smarter every day.

我是 Destin，你正在每天變聰明一點（Smarter Every Day）。

Have a good one.

祝你愉快。