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AK-47 水下射击

AK-47 Underwater at 27,450 frames per second (Part 2) - Smarter Every Day 97

嘿 我是Destin 欢迎收看Smarter Every Day我已经了解了不少在枪在水下的情形
Hey it’s me Destin welcome back to Smarter Every Day. So I’ve been learning a lot about guns underwater,
很酷 我是说 在第一集视频中我已经明白了稍后的行动中
which is pretty cool. I mean, in the first video I learned all about what’s happening back here
会发生什么 但问题是由于我装备的限制
in the action. But the problem is because of limitations in my setup I didn’t get to see
我无法见识到子弹在水中发生了什么 我真的超想看
what happened when the bullet exits and goes into the water. Now I really want to see that,
所以 我必须稍作思考 突然我灵光乍现 你看 我没有把枪放入注水的玻璃缸中
so I had to think about it for a while and I had an ah-ha moment. You see instead of building an aquarium
而是设计了这个 仅仅留下了水
that was keeping the water in with the gun, I built this, to keep the water out.
但问题是 尽管我做出了这么酷的装置 还弄到了一台
But the problem is, even though I built all this cool stuff and got my hands on one of the
商场中最好的高速摄像机 但是我腾不出来手拍摄了
best high speed cameras on the market, I didn’t have enough hands to run it all.
So I invited some friends to help me.
准备好了没 什么 好啦 酷毙了
It’s gonna work. – Yeah?
– Yeah.
– Sickeningly good.
(Destin) I was hoping to get
the widest view possible, that we can get inside that mirror.
所以 我们会尽量把广角镜头靠近镜子 否则我们将会只看见平台 我也是这样想的
– So, we’re gonna have to be as close to the mirror as possible with the wide angle otherwise we’ll see the rig won’t we. – I think so.
(Destin) What kind of lens do you think you’re gonna use? – Lens…
那你准备用中间那个 我们应该用镜头不是么 (大笑) 我们应该有一个镜头 (大笑)
So you’re gonna be in the middle. – So we should have a lens, shouldn’t we? [laughs]
– We should have a lens. [laugh]
– The problem with doing an AK under water is that
我没法使用相机,所以我请Slow Mo Guy来帮我
I can’t trigger the camera, so that’s the Slow Mo Guys who’ve come to help me.
所以你打算用什么机器 用Phantom v1610
So what are you gonna run? – Run the Phantom v1610 today which goes up to
18,000 frames per second at 720p.
我分不清他有多块 肯定比你的手指头要多
– I can’t count that high. – Definitely more than.. you’ve got fingers.
你能帮我拉下拉链吗 除非你来自阿拉巴马
– Can you zip me? – Unless you’re from Alabama.
– Alright just to show you how cold
当我们准备开始时 水温只有华氏40度
it is when we’re doing this, that’s about 40 degrees.
太冷了 所以相机将会拍摄最高处的这面镜子 然后向下走
And it is cooold. So the camera’s gonna look into the top mirror, it’s gonna bounce down
水下会有一个潜望镜 我将会在这个地方射击……
and then basically it’s a periscope under water. I’ve got the gun here…
You can see it there, with the phantom.
[gun cocking]
[gunshot] [bubbles]
[gun clearing]
[slowed down gunshot]
[multiple bangs]
好吧 这几次结果都很一致
Alright, it has been very consistent. We’re getting about
5-6 feet of bullet travel.
[slowed down gunshot]
[slowed down gunshot]
(步枪退膛)好了 我们刚刚看了什么
[gun clearing] OK. So, what did we just learn?
你会发现这里有气体冒出 产生非常多的小气泡
You can see that there’s gas that comes out right here. It’s a little gas bubble.
And the reason that’s happening is because it’s.. the piston is venting just
当它通过……(笑)我不能说我冷 当子弹
when it gets past… [laugh] I can’t talk I’m freezing. As the bullet goes
射出枪膛 穿过导气箍 压着气体推动活塞
down the barrel it passes this gas block and pushes gas against this piston.
现在你可以发现螺栓在移动 但是看看发生了什么
Now you can see it starts to move the bolt but watch what happens.
就在这 它从气体和枪的接口处打开这就是为什么射击时会冒出气泡了
Right there, it opens up this little gas port. That’s why there’s a bubble right
所以我如果把这个东西拿掉 你会发现活塞排气孔
there during the shot. So if we take this off, you can see that the piston
在前进后仅后退了1/4英寸 如果你想到了这些
vents after it goes only about a 1/4 of an inch back. If you think about
很棒啦 因为只需非常短的压力脉冲就足以克服
it that’s cool because this very short pressure impulse is enough to overcome all the springs
武器内部的弹簧的弹力和摩擦力 并使其循环往复 而这仅仅由于惯性力
and the friction in the weapon and cycle it, simply due to inertial forces.
[gunshot] [water spray]
天哪…..好冷 (笑声)
Oh gee.. it’s cold. [laughter]
好吧 所以现在我们来试试越肩发射
Alright, so… So now we’re gonna do over the shoulder?
是的 是的 越肩发射吧 行
– Yeah, yeah. Over the shoulder shot. – Alright.
(德斯廷)可以装弹吗 可以装弹
(Destin) All clear to load? – Clear to load.
– Clear to fire?
可以开火 3 2 1 (射击)
– Clear to fire. – 3.. 2.. 1.. [gunshot]
(Destin) Weapon’s clear.

– Ohh.
你拍到了没 我拍到了 我会检查一遍
– Did you get it? – I got it. I’ll go check it.
[slowed down gunshot]
[multiple bangs]
[slowed down gunshot]
[slowed down gunshot]
[underwater gunshot]
是好啦 我知道挺酷 但并不是那么酷 让我讲讲我是怎么想的
Yeah. I know that was gonna be cool, but not that cool. Let me try to explain what I think’s going on here.
我们看见了振荡 这你可以在设计后产生的气泡中看见 那非常炫
So we got this oscillation that you can see after the shot in the bubbles. That’s awesome.
我搞不懂为何气泡在破裂后又会重新产生 但这是怎么回事呢
I didn’t understand why the bubble would start back up after it collapsed. But here’s what’s going on.
有一个叫Rayleigh-Plesset 的方程 描述了气泡在水下的各种可能性
There’s an equation called the Rayleigh-Plesset Equation that describes everything a bubble does under water.
这很难用手去计算 你必须使用电脑去解决 不过基本上就是这么回事了
It’s too hard to solve by hand, you’ve gotta use computers to figure it out but this is basically what’s going on.
在反应起始点气泡内部具有极高的压力 并且开始
At the initiation point you have a super high pressure inside of a bubble and it begins to
向周围的液体传导动力 所以它开始变大 在某些点
impart momentum to the fluid around it so it begins to grow. At some point
它超越了气泡内压力等于外部压力的点 并且继续
it passes the point where the pressure inside the bubble is equal to the pressure outside the bubble and it continues
变大 直到最后停了下来 在现在的这个点 内部的压力极小
to grow until eventually the water stops it. Now at this point you have low pressure
所以它又再次破裂了 这是因为流体动能
inside and high pressure outside so it begins to collapse again, and because of fluid momentum
它再次超出了平衡点 并开始压缩
it goes again beyond that equilibrium point and begins to compress.
So it gets a super high pressure on the inside again and boom, another shock wave
然后重新开始这一过程并产生振荡 这种震荡现象直到耗尽
and the process starts all over again. This oscillation occurs until you dissipate
整个系统的动能才会停止 在气泡气体最致密的点
all the kinetic energy in the system. Now at this point of
受到最大的压力 在这一点有时会产生
tightest closure, you have the highest pressure. At this point sometimes something can occur
声致发光现象 这种现象发生在一个空穴作用的气泡
called sonoluminescence. Sonoluminescence occurs when you get a flash of light
收缩时产生发出瞬间闪光 就像我希望的那样这就是
when a cavitation bubble is collapsing. Now as much as I want to believe this
声致发光现象 我非常相信这是水塘上的阳光的一种非常酷的反射
is sonoluminescence I’m pretty sure it’s just a really cool reflection from the sunlight above the pool.
但是这个现象只发生在塌缩点上仍然很有趣 我奇怪为什么
But it’s still really interesting that it occurs at the point of collapse. I wonder why
会发生这一现象 好的 我们需要讨论些别的 这是我最喜欢的镜头
that’s happening. OK there’s something else we need to talk about. This is my favourite shot.
Originally I thought that the first gases out of the barrel were from where the bullet
并且弹壳产生的膨胀的气体在它周围流动 但再看一次
exits and the expanding gases from the cartridge flowed around it, but look again.
你看见这个沿着气泡长度的黑色痕迹了没 那是在子弹后面
Do you see that black colour trailing down the length of the bubble? That’s the burnt gunpowder being
射出的弹壳中燃烧完的火药 如果沿着气泡连接火药
released from the barrel behind the bullet. So if you follow that powder down the bubble, it should
它应该和子弹在一条线上 是的 就是那个 所以第一团白色是什么呢
line up with that bullet. Yeah, there it is. So what’s the first white cloud then?
如果有一正在流动的液体 你让其加速 那么这个液体的压力就会下降
If you have a flowing liquid and you speed it up, the pressure of that fluid drops.
现在看起来正如所说的一样确有一些下降了 但这就是所发生的
Now it seems a little bit backwards from how it should be, but this is what happens. It’s called
它被称做伯努利原理 在流速大的地方压强小 所以让我们来看下
the Bernoulli principle, where flow is high and pressure’s low. So let’s look at this
这个是水的示意图 水在4℃ 一个标准大气压下
phase diagram for water. The water we were in was about 4 degrees celcius and about
1 atmosphere. If we drop the pressure of the water below a certain point
则水就会变成水蒸气 我们射击前枪管中是不是充满了水
the water turns to vapour. The inside of the barrel was full of water before we
shot right? And so the bullet pushed it out at a very high speed. So where
所以流速大地方 压强就小 空穴作用发生在枪管中
flow is high, pressure’s low. Cavitation is happening in the barrel on the
的子弹的前方 我仍尝试仔细考虑这件事儿 但就是这样了
front side of the bullet. I’m still trying to wrap my head around this but there it is.
你在视频中可以清楚的看到 一旦子弹冲出这个空穴作用云团
You can actually see it in the video. Once the bullet punches out of this cavitation cloud something else
一些别的现象就发生了 你可以注意到 右边的气泡看起来像一朵云
is happening. You’ll notice that the bubble on the right looks like a cloud and the bubble
而左边的气泡看起来更像是玻璃 Andrew Davidhazy在子弹飞行过程中
on the left looks more like glass. Andrew Davidhazy took some awesome
拍下了一些爆炸图 这些图显示了子弹前面的冲击波
shatter graphs of bullets in flight which show the shock wave on the front of the bullet. The area behind
冲击波后面的区域压力更低 水变成了蒸气 因为
the shock wave is lower in pressure. It turns to vapour. Because this
这个低压区具有更平滑的流动边界 所以它看起来就像是玻璃
low pressure region has a smoother flow boundary it looks more like glass
而不是由我们枪管的乱流引起的模糊的云团 所以就是这样
instead of the fuzzy cloud look caused by the turbulent flow coming out of the barrel. So there you have it.
你从枪里不只会射出子弹 你会射出三种不同的东西
You’re not just shooting a bullet out of this gun, you’re shooting three different things.
现在我们清楚气穴背后的物理原理 你可以在告诉摄像机下清晰地看到这三样东西
Now that we understand the physics behind cavitation you can clearly see the effects of each of these three
各自的形态 是的 我们也明白了气泡的反弹现象 不是么
components in the high speed video. Oh yeah, and we also understand bubble bounce now too,don’t we.
在此非常感谢Gavin和来自Slow Mo Guys的Dan
So a huge thank you to Gavin and Dan the man from the Slow Mo Guys. They came all the
他俩想法设法来亚拉巴马州帮我拍视频 这欠了个大人情 所以我们重做了部视频
way to Alabama to help me shoot this video. That’s a pretty big deal. So we re-did a video
放在了他们频道上 是一些我之后做的事情 用v1610拍摄水下手枪射击
on their channel, something I did a while back, pistols under water, only we used a v1610.
很酷的 去他们频道看看吧 浪费不了你的时间
It’s awesome. Go check it out on their channel, it’s totally worth your time.
我频道上的视频是为了让你们感受下这个酷炫的视频 同时也能学点儿知识
On my channel the intent here was to make an awesome video that you enjoyed and you also learn something, and
没准还能得点儿捐献 所以 如果你认我们关系近了 我们可能发生了点化学反应
perhaps earn your subscription. So, if you think I got close, we got a little chemistry going on,
看看视频的第三部分 俄罗斯蛙人枪 是的 他俩回去了
check out part 3 of this video, Russian frogmen guns. Yeah, they exist.
所以我自己拍了这些 我仍然用了Ninja Scope3000(可能是潜望镜或者镜头) 或者你随便起个名字
So I got my hands on some of those. I still have the ninja scope 3000 or whatever we’re gonna call that thing.
你知道这是怎么回事 无论如何 我是Destin 你正在收看Smarter Every Day
You kinda see where this is going. Anyway, I’m Destin, you’re getting Smarter Every Day,
祝你有美好的一天 所以我们选这个池塘是有原因的
have a good one. So we actually selected this pool for a reason.
Jimmy Neutron住的地方很偏僻 所以 如果子弹射出 周围的人么都会很安全
Jimmy Neutron lives in the middle of nowhere, so if the bullet got away from us, everybody down range would be safe.
聪明点 请勿尝试 看看它怎样剪裁玻璃的
Please be smart, don’t try this. So check out how he cuts the glass.
[scratching] Huh?
(咔嘣)(Destin)什么 她刚才做了什么
[snap] (Destin) What? What did he just do?!
(大笑)(Destin)离我电脑远点 别碰我电脑
[laughs] (Destin) Get away from my computer, get away from my computer!
好的我们有子弹了 上面没什么损坏
Alright we got the bullets. There was no damage but
you can definitely see the grooves from the rifling in the barrel.
(字幕:Andrew Jackson)字幕由andrew.wordpress.com制作
[ Captions by Andrew Jackson ] captionsbyandrew.wordpress.com
欢迎大家用各种语言翻译 如果能提供帮助 请联系Destin
Captioning in different languages welcome. Please contact Destin if you can help.