In the 21st century, the indispensable requisites for a commercial sealift system that is to be deployed across the five oceans are high speed and stability, and such a high speed sealift system is demanded which operates at the super-high speed of 40 knots to 70 knots, and which is capable of marine transport, in a quick and safe manner, of perishable goods, expensive capital goods, and cargoes whose volume or weight makes it difficult for air transport, and strategic military goods, and also which is capable of large-scale deployment of forces, and particularly, of parts or equipment and materials which require timely arrival (just-in-time).
While the existing sealift technology has formulated and utilized the static force of buoyancy, the dynamic force due to pressure difference, lift, as well as the man-made external force of air pressure to build and develop the sealift system, it has not met the demand for high speed of the 21st century. To solve the above issues, while vessel shapes are modified, mono-hull fast ships with an appropriate Froude number and catamarans or trimarans for high speed stability have been developed to develop the super-high speed ship that can reach 70 knots. Nevertheless, such super-high speed ships can be driven based on their entire hull or part of the hull being underwater so that their thrust force per ton becomes elevated, which results in remarkable reduction of its environmental and economic characteristics. Therefore, a super-high speed and smooth sealift system that overcomes such difficulties can only be solved based on the new technology called “moving on the water surface”.
Searching for technology of the travelling on the water surface for the high speed sealift system of the present invention from natural phenomena, we find: the fact that the Basilisk lizard (so called Jesus lizard) runs on the water by treading water 20 times a second to catch its prey or to run away from predator threats (results of the research conducted by the Department of Biology at Harvard University, USA), and the fact that the concept of an elevation force is identified from the law of nature that “momentum change equals its impulse” related to Newtonian mechanics, and also we find the pebble skipping effect also known as “water sparrow” when a round and thin pebble thrown over the water results in its skipping on the surface of the water and eventually its sinking into the water; and we derive the concept of elevation force, and develop such concept into the principle of moving on water surface and apply this principle to tires: tires that can travel over the surface of water over a certain threshold speed were thus discovered, which has resulted in the birth of the high speed sealift system of the present invention.
According to the Advanced Mobility Concepts Study for the 21st Century, requirements for the future mobility platform are summarized as the following five items.
A sealift system equipped with the following capabilities is required:
(1) It shall be capable of drastically reducing dependence on fixed infrastructures such as a harbor.
(2) It shall be capable of entering various points with natural advantages.
(3) It shall be capable of quickly mobilizing troops into a combat position.
(4) It shall be capable of performing vertical mobility operations.
(5) It shall be capable of offsetting the difference in the period of time between troop deployment and combat participation.
Nevertheless, in designing the high speed sealift system, the technology known so far has utilized buoyancy, lift, and air pressure. In addition, in order to minimize the drag from navigation, the mono hull, the catamaran intended to maintain stability against wave height and trimarans are combined with air pressure, buoyancy, and hydrofoil effects to operate and develop the high speed transport system. However, the above five requirements have not been satisfied. Furthermore, while the ship with the wing-in-ground effect has been claimed to be able to carry a larger quantity of cargo at a speed exceeding 300 knots, it is thought to require verification over a long period concerning whether such an effect may also be available even under severe weather with rough waves.
The five requirements above that have been presented as demands by the Advanced Mobility Concepts Study of the 21st Century, cannot be satisfied by the prior art based on buoyancy, lift and air pressure or wing-in ground effect only, so a new sealift technology must be developed.
Therefore, the present invention started from the law of nature that “momentum change equals its impulse” of Newtonian physics as a new sealift principle, and it has been discovered that a certain rotating object that collides with water can travel on the water surface at higher speed above its threshold speed by a force that can mate with and rotate on the water surface, that is, the elevation force. The principle of moving on the water surface by the elevation force of the present invention may be described as follows:
When a tire “0” having the distribution weight of “ΔMg” in a certain transport system rotates at a certain angular velocity of “ω” on a certain face “10” (herein, the water surface), the its centrifugal force “FR” exerted on the applicable face “10” by the applicable distribution mass “ΔM” during the instant of contacting the applicable face “10”, “Δt”, is expressed as follows:
F
R
=ΔMRω
2 (1)
It is assumed that such centrifugal force “FR” act as the repulsive force by an equilibrium in response to the distribution weight “ΔMg” of the applicable system (Principle of Superposition), that is,
F
W
=ΔMg=ΔMU
2
/R=F
R (2)
Herein, the relation equation for the driving speed of the tire “0”, “U=Rω”, was used. The threshold speed “UCR” by which the centrifugal force of the tire reaches its force equilibrium with the distribution weight of the applicable system is expressed as follows:
U
CR
=√{square root over (Rg)} (3)
At such threshold speed “UCR”, the condition under which the applicable tire needs to stay on the water surface to become parallel with the water surface during the threshold instance “Δt” is described below:
μΔMg×Δt=ΔMUCR−0 (4)
Herein, “μ” was assumed to be the coefficient of coulomb rolling friction between the tire and the water surface. In addition, when the tire “0” collides vertically with the water surface, the condition under which the tire needs to stay on the water surface during the threshold instant “Δt” is given as follows, provided that the vertical speed component of the tire with respect to the water surface “10” is set as “V”:
ΔMg×Δt=ΔMV−0 (5)
Then the threshold instant “Δt” may be expressed as follows utilizing Equations (4) and (5):
Herein, assuming that the tire, upon contacting the water surface, collide with the water surface at the centrifugal acceleration of “aR=U2CR/R” during the threshold instant of “Δt”, the vertical speed component of the tire “0”, “V”, is given as follows:
On the other hand, the following relation equation is obtained from Equation (6):
Assuming that the applicable tire “0” mate and rotate under the rated friction condition (no slip condition) at the threshold speed of “UCR”, “μ=1.0” is established and then substituted into Equation (7) so that the value at the threshold instant is expressed as follows:
That is, when the applicable tire “0” travels at the threshold speed of “UCR=√Rg”, it stays on the water surface due to the repulsive force from the water surface during the threshold instant of “Δt=√R/g”, and if such condition is continuously satisfied, the applicable tire “0” naturally travels on the water surface “10”.
Now, since the present invention resulted in the discovery of the condition that enables the tire “0” to move on the water surface, the size and number of the tires “0” that are suitable for the high speed sealift system of the present invention may be determined based on the above. In addition, taking the transport stability of a system into account, its center of gravity is located in front of its center of pressure so that the numbers of front and rear tires may be determined according to weight distribution. The required power may be found from the following equation according to the maximum speed of the system, “Umax”:
In Equation (10), “ρ” is the density of water, “AD” the drag cross-section area of the system, and “η” a power efficiency, respectively. For example, if the total carrying weight of the high speed sealift system of the present invention is 2,000 tons and its maximum speed is 65 knots, 2 water jet pumps of 55,000 hp each are required.
When a high speed sealift system is designed and built according to the principle of moving on the water surface of the present invention and commissioned as the high speed sealift system, upon lowering its planning gears over its threshold speed and contacting the water surface with its applicable tires, the tire surfaces mate with the water surface and undergo rotation to enable them to travel on the water surface at such a high speed that the system becomes capable of marine transport in a quick and safe manner, of perishable goods, expensive capital goods, and cargoes whose volume or weight makes it difficult for air transport, and strategic military goods, and is capable of large-scale deployment of forces, particularly, of parts or equipment and materials which require timely arrival. In particular, it enables waterborne maneuvers and operations with troops and equipment in the combat stance required by the advanced mobility platform for the future and can advance into any seashore so that the seamless transition between troop deployment and combat participation may be maximally achieved, which effectively enables landing operations to be performed resolutely as required by the 21st century.
In addition, the high speed sealift system of the present invention represents an economic sealift system, wherein it has such high transport efficiency by travelling on the water surface with tires that it consumes as much power as that required for a vehicle to travel on a highway.
The present invention starts from the law of nature related to Newtonian physics that “momentum change equals its impulse” and leads to the discovery of the “principle of moving on the water surface” in which applicable tires mate with and rotate on the water surface at a threshold speed based on rolling friction during the threshold instant, and relates to application of the principle to the high speed sealift system. Specific application cases intended to implement the present invention are presented as examples.
As an example of the present invention, it starts from the law of nature related to such Newtonian mechanics that “momentum change equals its impulse” and leads to the discovery of the elevation force and then results in its advancement as the principle of moving on the water surface, wherein a series of theoretical implementation processes for application to tires are described, and the progress leading to the birth of a high speed cargo ship that satisfies the mobility platform for the future is described.
To support the above description, starting from the law of nature related to Newtonian mechanics that “momentum change equal its impulse,” and considering that the impulse to the mean force “ΔMg” with respect to the repulsive force “F(t)” that an applicable tire 0 exerts vertically on the water surface 10 during a certain threshold stay instant “Δt” is equal to the change in momentum “ΔM×V−0”, the elevation force which results from vertical collision between the tire 0 and the water surface 10, “ΔMg” and the elevation force which results from a horizontal partial force due to rolling friction, “μΔMg”, are generated so that the applicable tire 0 travels over the water surface 10 provided that the impulse to the mean horizontal repulsive force “μΔMg” becomes equal to the momentum change in a horizontal direction “ΔM×U−0”.
R=g×Δt
2 (11)
Then, the radius of the tire 0 becomes 0.715 m, and if a total of 80 tires are applied, the system distribution weight exerted on each tire is 25 tons and the internal surface area of the tire, At, is 806.45 cm2, so that the width of the tire 0 becomes 304.8 mm, and 16 tires on both side of the front and 64 tires on both sides of the rear are respectively mounted on the planning gear.
The present invention relates to a discovery of the elevation force based on the law of Newtonian physics that “momentum change equals its impulse” and to the high speed sealift system that is propelled according to the principle of moving on water surface by applying it to its tires, wherein 2-wheel motorcycles, 4-wheel passenger systems, and ground transportation vehicles carrying large cargoes that operate by using tires may be converted into sealift systems to apply the present invention in the same way that vehicles are driven on the highway, and also represents a high speed sealift system based on the advanced technology of moving on the water surface as being demanded in the 21st century whose scope may be expanded to high speed ferries, container vessels, and ultra-large oil tankers.
Number | Date | Country | Kind |
---|---|---|---|
10-2010-0061297 | Jun 2010 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/KR2011/004465 | 6/20/2011 | WO | 00 | 1/23/2013 |