The leading car of the Shinkansen has changed shape to counter "tunnel don"

The leading car of the bullet train is designed to be significantly different compared to the JR line and private railway vehicle. The shape with a sharp nose will receive an impression that speed seems to be exactly like it, but that shape is not simply a pursuit of speed, it is not what we arrived at, and it is not a thing that comes to micro-pressure waves accompanying high speed operation, so-called "tunnel don" It is a countermeasure, that you are incorporating biomimetic (biomimetic) on YouTube'sVoxThe channel picks it up.

The world is poorly designed. But copying nature helps. - YouTube


In 1989, the Shinkansen faced one problem.


The main operation of Tokaido and Sanyo Shinkansen was operated100 series. However, in order to further increase the speed, "problem solving" was necessary.


When the train enters the tunnel at high speed, a "compression wave" is created in the tunnel.


In the figure it seems that the train is pressing the compression wave, but in reality the compression wave propagates at the speed of sound (1225 km / h) and is emitted from the tunnel exit. This radiated pressure wave is called "micro-pressure wave" and it produces a big noise called "Don". For this reason "tunnel don" is also expressed.


It was Mr. Eiji Nakatsu who was a director of the JR West Examination Division and also a member of the Japan Wild Bird Society.


The problem was solved in 500 series.


First of all, it was a problem other than tunnel "pantographIt's wind noise.


Mr. Nakazu, who likes birds, knew that unique odd blades were on the feathers of owls that would not make a noise when flying, and adopted the mechanism in the pantograph. In the figure below, although improvements to the T-shaped pantograph were already done, improvement of Mr. Nakazu which made unevenness in the column part, and that it was able to reduce the noise by 30% Thing.


Also, the part of the base of the pantograph is made with reference to the Adelie penguin which can swim smoothly without great movement.


And, as a countermeasure against micro-pressure waves, we changed the shape of the leading car. When Nakatsu Mr. dropped to make several types of shape sample of the lead vehicle in the water, was the most gentle landing was a shape that mimics the kingfisher dive into the river to catch their prey.


500 series made reflecting Mr. Nakazu's debut in 1997. It is 10% faster than before, the power consumption is 15% less, and the noise was able to keep the 75 dB limit.


By the way, at the site of the Japan Wild Bird Society, a column written by Mr. Nakazu himself has been posted, and details on how to proceed with research etc. are detailed.

Kingfisher and 500 series Shinkansen train | Portal site enjoying wild birds BIRD FAN | Japan Wild Bird Society
https://www.birdfan.net/fun/etc/shinkansen/index.html


Information on tunnel micro-pressure waves is also summarized on the Railway Research Institute's website.

Tunnel micro pressure wave reduction measures | Research and development | Public interest Foundation Railway Integrated Technology Laboratory
http://www.rtri.or.jp/rd/division/rd51/rd5120/rd51200101.html