In front of the warship with a long Tuo what use? Seriously, it's very important.2017-01-09 23:59:37 48 ℃
Product: Popular Science in China
Production: cold wood fishing
Producer: Computer Network Information Center, China Academy of Sciences
There will be wind and waves......
So, we have the impression that the bow is like this:
Cleaving Washington aircraft carrier.
But the part we don't see is like this:
The United States Ford aircraft carrier assembly picture, in front of the bow, below the waterline is a long tuo.
Not only are aircraft carriers, but also other large cruise ships. Usually, we see the cruise is like this:
At present, the world's largest volume of the ocean liner queen Marie two, there are 15 restaurants and bars, 5 swimming pools, 1 casinos, 1 floor and 1 planetarium.
But in fact, it is so:
Note that the white arrow, standing is a person, not a seagull. (photo: James Morgan \/ Cunard Line)
Perhaps so, we will see more clearly:
This shape, how to say hello...... (photo: Hammelmann Oelde)
Here comes the question again? What is a long bow in front of the lump? What is the use? Is it more to install sonar devices?
This problem has a long history
In ancient times, on the east coast of the Mediterranean Phoenician (1200 BC - 539 BC), they are good at sailing and business, Phoenicians built ships, the front also has a protrusion.
The Phoenician ship
The Phoenician ship
If we go back in time, to ask the Phoenicians: you build the ship, as it has a front projection? But in order to show the glory?
They may say: "in order to knock each other!"
Perhaps...... The boat will be a little faster."
But this is why?
"Why so many? This question, you should ask god!"
Ancient people know what design may be more effective, but I do not know the reasons behind. Now, to tell the truth, we cannot paizhexiongkou said, hundred percent and understand the principle behind.
Why do you say that? First look at an example.
A $800 million cruise ship
The National Geographic Channel has produced a documentary about the queen Marie two. There's a story about it.
The cost of up to 800 million U.S. dollars of cruise ships, in its overall design has been set, the speed does not meet the requirements, only the speed of more than and 20. The ordering firm strongly demands that the cruise ship in calm sea must have close to or more than 30 of the speed, must have the ability to cross the the Atlantic within 6 days, otherwise the cruise will lose competitiveness!
However, the cruise propulsion system has started, can not think of ways to increase power. It may worry cruise manufacturers, finally, their designers helpless situation, the prominence of Queen Marie No. two bow in front of two meters long, then the problem is solved, the cruise speed was more than 30.
This projection, now we called the bulbous bow.
To commemorate the ten anniversary of Queen Marie, No. two,
Photographer James Morgan captain Kevin Oprey flicker to the prominence on the portrait (on the importance of the photographer!).
Yes, now we all know that the bulbous bow can improve the speed of the ship, but if we really know so well as Einstein most definitely not superluminal objects accurately, as we know the speed of light is equal to 299792458 meters per second, then, aided by a computer, perhaps all ship designers should know in advance. The exact length of Queen Marie two ship's bulbous bow should be 12 meters, or 12.005 meters, however, designers do not know, he is to take trial way.
Why the bulbous bow can accelerate?
The ship Yu Hai, like car on the road, the former is in the water and air through the junction, which is at the junction of air travel. And the deep diving submarine, it is more similar to the aircraft to take off air - all at a fixed working medium.
Therefore, for the ship, we must consider the air resistance of the atmosphere, but also consider the friction of water, as well as the wave resistance, that is, wave resistance. These resistance, Xing wave resistance and friction resistance accounted for the bulk of the high speed ship, these two types of resistance accounted for nearly half, accounting for about 85% of the total resistance.
The waves will make the boat down, this is somewhat similar to the way you are driving in a bumpy.
Undoubtedly, the waves will increase the resistance of the ship, and the calm sea, around the ship waves (wave) is caused by the ship itself, from the aspect of energy, the wave is made in the ship after consume large amounts of fuel, so we can say that the ship, the resulting wave is smaller, less then, the ship fuel consumption is small.
The waves of the bow, like a wall of water, always go with the ship.
Therefore, the key is to reduce the boat, especially the bow wave, how can we reduce?
After a lot of practice and previous experiments, it was found that the effect of bulbous bow!
But this is why?
There is an explanation for this.
To move a ball on the surface of the water, the water pressure in front of the ball rises, the top surface of the water will rise, to the back of the ball, the pressure drops, the water surface to fall, thus playing a role in inhibiting waves.
The explanation is from the Japanese ship expert Yoshida Wenji, who mentioned it in his book, ship knowledge.
With this picture, we may be able to understand Yoshida Wenji's argument more easily. Pictured Italy ship Pride of Hull.
Another explanation is that, is a bulbous bow wave generated with other wave superposition, the equivalent, you met his crest trough - offset.
(dynamic map) ship, if not bow, wave climb, the impact of the bow, the formation of great resistance.
(dynamic map) gradually lengthened bulbous bow, the formation of the wave and another wave offset each other.
The ship is sailing at a constant speed, and the speed of change will undoubtedly lead to the bow in front of the flow state change, corresponding to this situation, people are starting to study variable bulbous bow.
Different speed, can adjust the bulbous bow shape and angle, until it can minimize the wave resistance. (picture from Daehwan)
During World War II, the Japanese Battleship Yamato, the displacement of up to 64000 tons, 263 meters long, can be equipped with 7 aircraft.
In order to let the Japanese Battleship Yamato to 27 knots in full load condition, equipped with large power system. However, because of the large number and installation of the bulbous bow, the result, it satisfies the 27 knots under the condition of low output power 8.2%, equivalent to a reduction of 12 thousand horsepower output.
The Japanese Battleship Yamato, a top speed of 27.46 knots.
In April 7, 1945, the ship was sunk and the picture, a total of 2767 people, only 269 people survived.
More bulbous bow
To understand the mechanism of bulbous bow in the rough, we may wish to enjoy other bulbous pictures.
The huge bulbous bow, as compared with two on the ground. (picture from S*anner06n2ey)
The USS Welsh, Prince of Wales, under construction. Pictured above is the bulbous bow, carrier deck. Expected to serve before and after 2020. (Photo by Grant Amy)
The sea lion said: actually, this is the first time we climbed up the ship, take a nap before the warm sunshine. It is said that for a while to ride the wind and waves is exciting. (picture from Tony Lindeque)
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In this paper, the integration of science and technology produced by China, reproduced please indicate the source.
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