英伦广角 打喷嚏形成的气流移动速度飞快

 

Sneeze and cough particles form a cloud whose turbulence¹ pulls in surrounding air, which allows the goop to maintain buoyancy and move farther than expected. Cynthia Graber reports.

Gordon: “When you have to sneeze or cough, do it into the bend of your arm.”

Elmo: “Sneeze into your arm with Elmo. Ah-choo!”

Gordon and Elmo from Sesame Street are right. And MIT researchers recently found that viruses can travel much further than we thought. Which shows how important it is to block coughs and sneezes.

The researchers used high-speed imaging of folks coughing and sneezing, along with simulations and mathematical models. The new research shows that multiple drops travel in a cloud. And the cloud’s turbulence pulls in surrounding air, which allows the goopy assemblage to maintain buoyancy and move farther.

Heavier particles drop out first, but about five times further out than had been previously² predicted. And the small ones swirl³ around and can be carried 200 times past previously predicted distances. The research is in the Journal of Fluid Mechanics. [Lydia Bourouiba, Eline Dehandschoewercker and John W.M. Bush, Violent expiratory events: on coughing and sneezing]

Longer flight distances means coughs and sneezes can often reach ventilation systems. The researchers thus encourage hospital and airplane engineers to consider designs that block droplet⁴ flight and thus keep everyone else from catching⁵ your cold.

1 turbulence   

n.喧嚣，狂暴，骚乱，湍流

参考例句：

• The turbulence caused the plane to turn over.空气的激流导致飞机翻转。
• The world advances amidst turbulence.世界在动荡中前进。

2 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

3 swirl   

v.(使)打漩，(使)涡卷；n.漩涡，螺旋形

参考例句：

• The car raced roughly along in a swirl of pink dust.汽车在一股粉红色尘土的漩涡中颠簸着快速前进。
• You could lie up there,watching the flakes swirl past.你可以躺在那儿，看着雪花飘飘。

4 droplet   

n.小滴，飞沫

参考例句：

• The rate of droplet growth under different conditions can be evaluated.可以计算在不同条件下的云滴增长率。
• The test results showed that increasing droplet size was associated with better stability.试验结果表明，增加液滴尺寸将使稳定性提高。

5 catching   

adj.易传染的，有魅力的，迷人的，接住

参考例句：

• There are those who think eczema is catching.有人就是认为湿疹会传染。
• Enthusiasm is very catching.热情非常富有感染力。