The physics of surfing - Nick Pizzo

譯者: Lilian Chiu 審譯者: Helen Chang

Whether or not you realize it,

不論你是否知道，

as a surfer you’re a master of complicated physics.

身為衝浪者，你其實是個 精通複雜物理的大師。

The science of surfing begins

在你和你的衝浪板一接觸到水時， 衝浪的科學就開始了。

as soon as you and your board first hit the water.

The board’s size and light construction help it displace a lot of water.

衝浪板的大小以及很輕的結構， 協助它能排開很多水。

In turn, a buoyant force

這會產生一股浮力向上推，

equal to the weight of the displaced water pushes up,

力量大小等同於 被排開的水的重量，

counteracting you and your board’s weight.

可以抵銷你和你的衝浪板的重量。

This lets you stay afloat while you wait to paddle for a wave.

這就讓你能夠一直浮在海面， 等著為下一波浪開始划水。

And what exactly are you waiting for?

你在等的到底是什麼？

The perfect wave, of course.

當然是在等完美的浪。

Like other waves in physics, ocean waves represent a transfer of energy.

和物理的其他波一樣，

海浪（波）代表的是能量的傳遞。

Wind blowing across the ocean accelerates water particles near the surface,

風吹撫過海洋表面， 讓靠近表面的水粒子加速，

leading to the growth of ripples that become waves.

導致漣漪變大，成為海浪。

These deviations from the flat surface are acted upon by gravity,

這些從平坦表面偏離的 現象會受到重力影響，

which tries to restore the surface to its original flat state.

重力會試圖將表面 恢復成原本的平坦狀態。

As the waves then move through the water,

海浪接著會在海上移動，

particles push and pull on their neighbors through the wave induced pressure,

粒子會透過海浪推拉它們 附近的鄰居，導致壓力產生，

and this motion propagates energy through the water in unison with the wave motion.

這種運動會配合海浪的運動， 透過水來傳播能量。

The motion of these particles

這些粒子的運動

is much more limited than the overall motion of the waves.

相對於海浪的整體運動， 是更受限許多的。

Near the shore,

在靠近岸邊處，比較淺的 海底會限制海浪的運動，

the shallower seafloor constrains the motion of the waves

to occur in a more limited region than out at sea,

只能在比較受限的區域中 產生海浪，不像大海那麼廣，

concentrating the wave energy near the surface.

因此會把海浪能量 集中在靠近表面處。

If the topography of the shoreline is even and smooth,

如果海岸線的地形是平坦平順的，

this will refract the waves to become more

就會將海浪折射，

在它們靠近海岸時， 變得與海岸更平行。

parallel to the shore as they approach.

This is the crucial moment.

這是關鍵時刻。

As the wave gets near,

當海浪靠近時，

you quickly pivot your board in the same direction as the wave

你很快地轉動你的衝浪板， 和海浪同方向，

and paddle to match its speed.

並划水以配合上它的速度。

Your board forms an angle with the water,

你的衝浪板和水之間 會形成一個角度，

and this creates a dynamic pressure on the bottom of it,

這就會在衝浪板底下 產生出動態壓力，

forcing you and your board out of the water,

迫使你和你的衝浪板浮在水面上，

to skim along the surface.

沿著表面掠過。

At the same time,

同時，

your increased forward momentum makes you more stable,

你向前的動能會增加， 讓你更穩定，

allowing you to stand up and surf along the wave.

你便可以站起來，順著海浪衝浪。

Now you’ve caught the wave,

現在，你追到海浪了，

and are riding along its front face parallel to the shoreline.

正和海岸線平行的 海浪前緣乘著浪。

Fins on the surfboard allow you to alter your speed and direction

衝浪板的舵讓你 可以改變速度和方向，

by repositioning your weight.

做法是重擺你重量的位置。

Above you is the wave’s crest,

浪峰在你上方，

where the water particles are undergoing their greatest acceleration.

浪峰的粒子有最快的加速度。

That forces them to move faster than the underlying wave,

因此它們的移動速度 會比下方的海浪更快，

so they shoot ahead before falling under gravity’s influence.

所以在受到重力影響落下之前， 它們會飛快向前移動。

This forms the waves’ characteristic curls, or jets,

這就形成了海浪 很著名的特徵：拱波，

as they break along the shore.

會在海浪沿著海岸被破壞時產生。

Sometimes, the curl might completely enclose part of the wave,

有時，拱波可能會 將海浪的一部分完全包起來，

forming a moving tube of water known as the barrel.

形成一個移動式的水管， 也就是波捲狀海浪。

Because of irregularities in the seafloor and the swell itself,

因為海底和湧浪本身是不規則的，

few barrels last as long as the legendary 27-second ride off the coast of Namibia.

很少有波捲狀海浪能維持超過

納米比亞海岸的 傳奇性記錄：27 秒。

But many who manage to get barreled

但許多能夠在波捲狀 海浪中衝浪的人

have said they feel time passing differently inside,

都說他們覺得在浪中的 時間是不同步的，

making it one of the most magical experiences a surfer can have.

讓它成為衝浪者所能享受到 最神奇經驗之一。

Of course,

當然，海灘並非生而平等。

not all beaches are created equal.

Offshore underwater canyons or rock formations

近岸的水底峽谷或岩石形成，

in certain locations like Nazare, Portugal or Mavericks, California

比如在葡萄牙納扎雷 或加州麥沃瑞克斯這些地方，

refract the incoming wave energy into a single spot,

會把進入的海浪能量 折射到單一點上，

creating massive waves sought by surfers worldwide.

創造出全世界衝浪者 都在尋求的大浪。

And some of these waves travel for more than a week,

有些海浪能持續超過一個星期，

with swells originating more than 10,000 kilometers away from shore.

湧浪源自距離海岸 超過一萬公里以外的地方。

Waves surfed in sunny California

在陽光加州所衝的浪，

may have originated in the stormy seas near New Zealand.

可能源自紐西蘭 附近的暴風雨海洋。

So while you may not be thinking about weather patterns in the South Pacific,

你可能不會去想 南太平洋的天氣模式、

tectonic geology, or fluid mechanics,

構造地質學，或流體力學，

the art of catching the perfect wave relies on all these things and more.

但追上完美海浪的藝術

卻要仰賴上述這些及其他的東西。

And the waves we surf, created by wind,

我們衝的浪是由風造成的，

are just one visible part of the continuous oscillation of energy

它們只是能量持續振盪的 可見部分而已，

that has shaped our universe since its very beginning.

從宇宙最初，這種能量持續振盪 就一直在形塑我們的宇宙。