The Flettner rotor-powered ship

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The Flettner rotor-powered ship

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돌아가는 큰 원통으로부터 추진력을 얻는 배를 말한다. 

흔히 배는 프로펠러를 물에 넣어 물을 밀어내면서 반작용으로 추진력을 얻는다. 혹은 돛을 이용해 바람의 힘으로 추진력을 얻기도 한다. 하지만 플레터너 로터 배(Flettner rotor-powered ship)는 마그누스 효과를 이용한 배를 말한다. 

바람으로 큰 원통을 돌아가기 시작하면, 추진력이 발생하기 때문에 친환경 배라고 불릴 수 있다.  

원리

간략하게 설명하자면,

바람이 불면 원통이 돌아가고, 원통의 앞면과 뒷면의 압력차가 발생한다. 이 압력의 차이때문에 배가 이동하게 된다. 

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한마디로 마그누스 효과를 이용한 것이다. 자세한 내용은 링크 참조

마그누스 효과 보러가기

One final fascinating application of the principle is the rotor-driven ship designed by the German naval engineer Anton Flettner and built in 1925. The ship, the Buckau, had its masts and sails replaced by two vertical cylindrical rotors 12 m tall and with a diameter of 2.7 m.

They were rotated about a vertical axis by two 11 kW electric motors below decks to a maximum speed of 125 r.p.m. Just like the spinning ball, the combination of wind speed and rotor speed produced a force that propelled the ship through the water.

It was found that the Buckau could sail a full 20degree closer to the wind than a traditional sailing ship, and that she could reach a speed of 14.3 km hr-1 when driven by rotors alone compared with 14.5 km hr-1 when using a traditional propellor.

When a cylinder rotating around its own axis is exposed to an airflow moving at right angles to that axis, the cylinder experiences a lateral force that acts at right angles to the airflow and the axis of rotation. This force is known as the Magnus force after its discoverer.

     A vertical cylinder rotates clockwise

     The wind comes from the West

     The Magnus force pulls the cylinder to the North

발명가

Anton Flettner (1885–1961) was a mathematics and physics teacher, but his passion was technology. At the age of 29 – just before the outbreak of the First World War – he invented military devices (a controllable torpedo, a remote-controlled combat vehicle) which were rejected as infeasible, however.

In the 1920s Flettner began trying to find better ways of improving sails on ships. He tested rigid metal structures to optimize the aerodynamics of a sail to achieve significantly higher efficiency. While engaged in this work he learned that the Aerodynamic Research Facility in Göttingen was working on rotating cylinders to make a quantitative study of the "Magnus effect". This gave Flettner an idea.

Doomed to failure – forever?

Flettner's invention did not succeed in his lifetime. The gain in wind energy was not enough to compensate for the energy needed to drive the rotating cylinder, so that the propulsion system was not economical. Today the Flettner rotor is again being tested as a supplemental propulsion system for freighters, competing with other improvements in sailing technology such as kites. What all of these methods have in common is that they can save up to one-third in fuel costs.

적용 사례

Buckau 

E-Ship 1 

참고 

http://www.monorotor.com/history/

http://www.thiiink.com/history-of-flettner-rotor/

http://www.schoolphysics.co.uk/age16-19/Properties%20of%20matter/Fluid%20flow/text/Fluid_flow/index.html

http://www.ship-efficiency.org/onTEAM/pdf/06-STG_Ship_Efficiency_2013_100913_Paper.pdf

E-SHIP 1.pdf

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2015. 04. 13 작성

2016. 03. 02 추가 

1. http://www.deutsches-museum.de/en/information/young-people/inventors-trail/drivetrains/flettner-rotor/ [본문으로]
2. http://www.transtutors.com/questions/the-original-flettner-rotor-ship-394209.htm [본문으로]
3. http://www.schoolphysics.co.uk/age16-19/Properties%20of%20matter/Fluid%20flow/text/Fluid_flow/index.html [본문으로]