WO2018188556A1

WO2018188556A1 - Manufacturing method for air permeable metal housing structure which reduces fluid resistance to moving object and application thereof

Info

Publication number: WO2018188556A1
Application number: PCT/CN2018/082333
Authority: WO
Inventors: 周照耀
Original assignee: 周照耀
Priority date: 2017-04-13
Filing date: 2018-04-09
Publication date: 2018-10-18
Also published as: CN108723108A

Abstract

A manufacturing method for an air permeable metal housing structure which reduces fluid resistance to a moving object, comprising: first, weaving metal fiber yarns to form a weave slab, then sintering same, and pressing the sintered fiber yarn slab by means of plastic processing, so as to compress the pore size of the sintered fiber slab, reducing porosity of the material, improving the mechanical property of the material, and maintaining communication between the pores of the material, so as to obtain an air permeable fiber metal plate; after that, using a plastic pressure processing method to make the air permeable metal plate have the shape and size of the housing of a moving object, so as to obtain an air permeable housing structure, such that one side of the multi-microporous air permeable metal plate material forms the outer surface of the housing of the moving object, and the other side thereof forms the inner surface of the housing of the moving object, forming an enclosed space. Pressure gas outputted from a gas source enters the enclosed space, and the gas penetrates through the multi-microporous air permeable metal housing material from one side of the multi-microporous air permeable metal housing to the other side of the multi-microporous air permeable metal housing, meanwhile the air permeable metal material can also maintain the structural shape of the moving object housing and satisfy the requirement of structural strength.

Description

Method and application for manufacturing gas permeable metal shell structure for reducing fluid resistance to moving objects

Technical field

The present invention relates to the technical field of reducing fluid resistance, and more particularly to a method and application for manufacturing a gas permeable metal shell structure that reduces the resistance of a fluid to high speed moving objects.

Background technique

The hull surface gas layer (ie, air curtain) drag reduction technology can significantly reduce ship resistance, reduce fuel consumption, and increase ship speed, which has important economic and environmental value. The basic principle of the technology is to inject air or host exhaust gas between the outer surface of the ship and the water to form a thin uniform and stable gas-liquid two-phase flow, and use the difference in density and viscosity of water and air to change the surface flow of the hull. The viscosity, density and turbulence mode of the field reduce the actual wetted area of the vessel and thus reduce frictional drag. Experiments have shown that the surface friction resistance of the flat plate and the rotating body can be reduced by 50% to 80% under appropriate jet flow rate and appropriate water flow rate. The research experience at home and abroad shows that the gas layer drag reduction technology can reduce the navigational resistance of the ship by 15%~25%; it can be used on high-speed ships to increase the speed by about 10%~20%. It can be used on low-speed ships, saving the host power by 6%~ 10%. It does not require the formation of an air cushion between the hull and the water surface like a hovercraft, so it does not require a large amount of power to effectively reduce the resistance.

Wuhan University of Technology (References: Wang Jiayu, Zheng Xiaowei, Jiang Mansong. Experimental study on the effect of ship draft on the effect of microbubble drag reduction[J]. Ship Engineering, 2004(9): 9-12; Ship microbubble reduction under different jet forms Experimental study on the resistance pool [J]. Journal of Huazhong University of Science and Technology (Natural Science Edition), 2004 (12): 78-80) With the help of large-scale flat-bottomed ship model, the effects of ship draft and jet form on the drag reduction effect of air curtain Experimental research. In the test, porous silicon material plates were installed in the first and middle portions of the bottom of the ship model to generate micro-bubbles. Contrast tests on the effect of draft on the drag reduction rate were carried out in different towed speeds and different jet volumes in large towed pools. The test results show that only when the first jet and the first and middle volumes are simultaneously jetted and Fr≤0.646 (Fr is the length of the ship's length), the drag reduction effect is good when the shallow draft is used, and the total drag reduction rate is 32.8%. However, since the porous silicon material plate is used to generate microbubbles, the porous silicon material plate is difficult to process, the bottom of the ship can only be made into a flat shape, and the bottom of the ship cannot be integrally formed into a gas permeable structure, which hinders the practical application of the technology.

Summary of the invention

The object of the present invention is to overcome the deficiencies and shortcomings of the prior art, and to provide a method for manufacturing a gas permeable metal shell structure that reduces the resistance of a fluid to a high-speed moving object, which is safe and reliable, has a small amount of engineering, is easy to manufacture, and has low overall cost.

In order to achieve the above object, the technical solution provided by the present invention is: a manufacturing method of a gas permeable metal shell structure for reducing the resistance of a fluid to a moving object. First, the metal fiber yarn is woven to form a braid slab, and then sintered, and then Pressing the fiber slab to slab by plastic processing, compressing the pore size of the fiber sinter, reducing the porosity of the material, improving the mechanical properties of the material, while maintaining the pores of the material, obtaining a ventilated fiber metal sheet; and then passing the permeable metal sheet The plastic pressure processing method is manufactured into a shape and a size of a casing of a moving object, and a permeable outer casing structure is obtained, such that one side of the microporous permeable metal sheet material forms an outer surface of the moving object casing, and the other side forms an inner surface of the moving object casing, and Forming a closed space; the gas source outputs pressure gas into the enclosed space, and the gas permeates through the microporous gas permeable metal shell material from one side of the microporous gas permeable metal shell to the other surface of the microporous gas permeable metal shell while venting the metal The material can maintain the structural shape of the moving object shell and meet the strong structure Degree requirements.

The metal fiber yarn is woven to form a braided slab, which is first woven into a metal mesh cloth strip, and then the metal mesh cloth strip is tightly wound to form a layer of the outer layer material tightly covering the inner layer material. Coated roll-up slab body.

The metal fiber yarn is woven to form a woven slab, and the metal fiber tow is woven into a woven slab.

Uniformly distributing a layer of powder on the fiber slab, and then rolling the powder on the fiber slab, and then sintering the powder layer to bond the powder to the fiber slab and maintaining the powder granule The pores are connected to each other to obtain a gas permeable metal sheet whose pore size is distributed along the thickness step. The pore size of the microporous gas permeable material is stepwisely distributed, the inner surface pore size is large, and the outer surface pore size is small.

The outer casing of the moving object is made of a gas permeable sheet having a plurality of micropores, and is a single layer shell structure.

The outer shell of the moving object is a double-layer shell structure, the outer layer is made of a gas permeable sheet material with a plurality of micro-pores, and the inner layer is made of a dense non-porous metal structure sheet, and the inner layer and the outer layer are closed spaces. The gas source and the enclosed space are connected by pipes, and the pressurized gas can be input into the closed space through the pipe.

When the moving object moves at a high speed, the gas source injects pressure gas into the closed space, so that the pressure of the gas in the closed space is stronger than the pressure of the external gas, and the pressure gas in the closed space penetrates through the connected pores of the microporous material. The microporous material shell reaches the outer surface of the shell of the microporous material to form a gas layer having the same velocity as the moving object, and blocks the external fluid from directly acting on the outer surface of the microporous material shell, thereby reducing or eliminating the external fluid to the high speed. Resistance to moving objects.

The sensor of the information collecting system is placed in the closed space, collects the pressure information of the closed space, and transmits the pressure information to the control system, the control system controls the valve on the pipeline, controls the opening and closing of the pipeline, and the flow of the gas and the closed space. pressure.

The pressure gas in the enclosed space is subjected to ultrasonic vibration.

The application of the method for manufacturing a gas permeable metal shell structure that reduces the resistance of a fluid to moving objects, such as a locomotive, a high speed train head, a car, an aircraft head, a projectile, a missile, a torpedo, a ship, a submarine, an underwater vehicle Made of a permeable metal shell structure.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The process of manufacturing the ventilated metal shell by metal fiber woven, sintered and shaped processing is short, the pore size is easy to control, the method is simple and reliable, and the quality is easy to ensure;

2, can reduce or eliminate the resistance of air or water to the transportation vehicle, thereby increasing the speed of travel, reducing the time consumption of the road, and improving work efficiency;

3. When the external fluid is air, the outside air will not directly act on the high-speed moving vehicle, the vehicle operation will be more stable, and the safety and reliability will be improved;

4. When the external fluid is water, a mixed fluid layer of bubbles and water is formed between the water and the moving object, reducing the resistance of the water to the high-speed moving object, and increasing the moving speed in the water;

5, can reduce air resistance or water resistance to cause energy consumption of transportation vehicles, save energy, increase maximum travel, and reduce transportation costs;

6. The speed of the missile or torpedo is greatly improved, shortening the travel time and reducing the possibility of being intercepted by the anti-missile system;

7. When the plane throws a bomb from a high altitude, the speed of the bomb can be greatly increased, and its landing kinetic energy is also greatly improved. At the same time, the front of the bomb thrown from the high-altitude aircraft forms a gas layer with the same speed as the moving object, when the warhead and the ground When concrete, steel, and rock collide, the gas layer has a protective effect on the head of the bomb, which helps to increase the depth of the bomb into the ground;

8, the structure is simple, easy to manufacture and control, the cost of manufacturing and use is very low;

9. The method of the invention can be applied to the manufacture of vehicles, missiles, and artillery shells such as rail vehicles, aircrafts, land vehicles, water transport vessels, etc., and has a wide application range, which can generate huge economic benefits.

DRAWINGS

1 is a schematic structural view of a casing of a moving object of Embodiment 1.

2 is a schematic structural view of a casing of a moving object of Embodiment 6.

3 is a schematic view showing the structure of the outer casing of the moving object of Embodiment 10.

detailed description

The invention will now be further described in connection with a number of specific embodiments.

Example 1

The technical solution provided by the invention is: a manufacturing method of a gas permeable metal shell structure for reducing the resistance of a fluid to a moving object, firstly, the metal fiber yarn is woven to form a braid slab, then sintered, and then the fiber is pressed by plastic processing. Wire sintered slab, compresses the pore size of the sintered billet, reduces the porosity of the material, improves the mechanical properties of the material, and maintains the pores of the material to obtain the ventilated fiber metal sheet; then the ventilated metal sheet is manufactured by plastic pressure processing Forming and sizing the outer shell of the moving object to obtain a permeable outer shell structure, such that one side of the multi-microporous permeable metal sheet material forms an outer surface of the moving object shell, and the other side forms an inner surface of the moving object shell, and constitutes a closed space; The source output pressure gas enters the enclosed space, and the gas permeates from the side of the microporous gas permeable metal shell through the microporous gas permeable metal shell material to the other surface of the microporous gas permeable metal shell, while the gas permeable metal material can maintain the moving object The structural shape of the outer casing and the structural strength requirements are met.

In the present embodiment, a 35-micron diameter 1Cr18Ni9 stainless steel wire material is used, which is tightly woven into a stainless steel metal cloth having a width of 1 m by a braiding machine, and one end of the stainless steel mesh cloth tape is fixed at 8 mm thick and 40 mm wide. On the 1200 mm long core board, the motor drive mechanism rotates the shaft of the core board, and the stainless steel mesh belt is tightly wound on the core board, and the ends are aligned to form a layer of the outer layer material closely covering the inner layer material. The coated stainless steel mesh cloth has a plate-shaped rolled-up blank body; after the outer dimension reaches the required thickness of 10 mm, the stainless steel mesh cloth strip is cut short, and the stainless steel mesh cloth roll-up blank body is bundled with the steel wire to keep the rolled-up blank body Will be loose, and then the stainless steel mesh belt roll stack body is placed in a vacuum sintering furnace, heated to 1320 degrees Celsius, heat preservation for two hours, sintered stainless steel mesh belt roll stack body, between the mesh belt material layer and layer, Metallurgical bonding between the wires; after sintering, the sintered slab material is rolled by a plate mill to densify the blank material, reduce the voids in the blank material, and roll and manufacture Get Gap permeable sheet metal structure, and then by press molding a housing part. 1 is a schematic view of a casing of a moving object missile according to the present embodiment. The outer casing of the missile is a single-layer shell structure, and a ductile outer casing 1 is manufactured by using a ventilated stainless steel plate. The porous pores of the permeable stainless steel sheet have a pore size of less than 5 microns. One side of the microporous ventilated stainless steel plate constitutes the outer surface of the missile casing which is formed by the action of air, and the other side forms the inner surface of the ballistic outer casing, and constitutes a closed space 2 in which a liquefied gas cylinder is provided (for the gas source, The figure is not shown.) The liquefied gas is installed. Before the missile is fired, the valve of the liquefied gas cylinder is opened by the control system, and the liquefied gas is released into the closed space 2, so that the gas pressure of the closed space 2 reaches 2 atm and passes through the control system. The gas pressure in the closed space 2 is maintained at 2 atmospheres. The ventilation control system controls ventilation flow, ventilation time, and pressure. Since the gas pressure in the enclosed space 2 is greater than the atmospheric pressure outside, the gas in the enclosed space 2 passes from the micropores of the microporous stainless steel plate through the missile casing material to the outer surface of the microporous missile casing. The breathable metal material is 5 mm thick and can maintain the structural shape of the missile casing and meet the strength requirements. After the missile is launched, the gas in the enclosed space 2 has the same speed of motion as the missile. When it penetrates the outer surface of the missile casing, it also has the same speed of motion as the missile. A missile with a moving object is formed on the outer surface of the missile casing. The gas layer of the same speed blocks the outside air from directly acting on the outer surface of the missile casing, thereby reducing or eliminating the resistance of the outside air to the high-speed motion missile, so that the missile can achieve higher flight speed, shorten flight time, and reduce the anti-missile system. The possibility of interception.

Example 2

Different from the first embodiment, in this embodiment, 200 wires of 20 steel wires having a diameter of 50 micrometers are used, and the knitting machine performs multi-bundle weaving, and weaving a woven plate body of 2000 mm, 300 mm in width and 10 mm in thickness, and then weaving. Sintering at a temperature of 1250 ° C for 2 hours, metallurgical bonding between the wires, obtaining a sintered slab body, and then placing the sintered woven plate material blank between the rolls of the sheet rolling mill at room temperature for rolling, compressing the fiber The pore size of the sintered billet reduces the porosity of the material, improves the mechanical properties of the material, and maintains the pores of the material, obtains a 5 mm thick ventilated fiber metal sheet, and then processes the ventilated fiber sheet into a shell shape of the moving object and size.

Example 3

Different from the embodiment 1, in this embodiment, a layer of stainless steel powder is evenly distributed on the fiber-spun blank, the stainless steel powder is 100 micrometers, and the stainless steel powder is rolled on the fiber-sintered slab, and then the stainless steel is sintered. a powder layer, the stainless steel powder is combined on the fiber slab, and the pore communication between the powder particles is maintained, and a gas permeable metal sheet having a pore size along the step of thickness is obtained, and the pore size of the microporous gas permeable material is stepwisely distributed. The pore size of the fiber surface is 100 μm, the pore size of the powder surface is 5 μm, the thickness of the gas permeable layer is 5 mm, and the thickness of the gas permeable powder layer is 0.5 mm.

Example 4

Different from the first embodiment, the raw material for manufacturing the gas permeable metal sheet of the present embodiment is an aluminum alloy wire, a titanium alloy wire, and other alloy wires.

Example 5

Different from Embodiment 1, the moving object of this embodiment is a bomb thrown by the aircraft to the ground.

Example 6

A bundle of 20 steel wires with a diameter of 50 micrometers is used as a bundle. The braiding machine performs multi-bundle weaving, weaving a woven slab body of 2000 mm, 300 mm wide and 5 mm thick, and then sintering at a temperature of 1250 ° C for 2 hours. Metallurgical bonding between the materials is achieved, the sintered slab body is obtained, and then the sintered woven plate material blank is placed between the rolls of the plate rolling mill at room temperature for rolling, compressing the pore size of the sintered slab and reducing the porosity of the material. Rate, improve the mechanical properties of the material, while maintaining the pores of the material, to obtain a ventilated fiber metal sheet. Then uniformly distribute a layer of stainless steel powder on the gas-permeable fiber metal plate, the stainless steel powder is 100 micrometers, and then roll the stainless steel powder on the fiber-spun slab, and then sinter the stainless steel powder layer to make the stainless steel powder be combined with the fiber-reinforced slab On the plate, and maintaining the pore communication between the powder particles, a gas permeable metal plate whose pore size is distributed along the thickness step is obtained, and the pore size of the microporous gas permeable material is stepwisely distributed, and the pore size of the fiber surface is 100 μm, the powder surface The pore size is as small as 5 microns. The ventilated fiber metal sheet is then machined into the shape and size of the ballistic outer casing 3 of FIG.

2 is a schematic view of the outer casing of the moving object missile of the present embodiment. The outer shell of the missile is a double-layer shell structure, and the inner shell 1 of the tunnel is made of a common dense non-porous metal plate, and the outer shell 3, 7 is made of a gas permeable metal plate. It is a support block between the inner layer and the outer layer, and the space between the inner layer shell 1 and the outer layer shell 3 is a

closed space

2, 4 is a gas compressor (which is a gas source), 5 is a pipe, and 6 is a pipe. The valve controls the opening and closing of the duct 5, and the space 8 of the head is in communication with the enclosed space 2. The sensor of the information acquisition system (not shown) is placed in the enclosed space, collects the pressure information of the enclosed space, and transmits the pressure information to the control system. The control system controls the valves on the pipeline to control the on and off of the pipeline and the gas. Flow and pressure in the enclosed space. The gas compressor 4 delivers compressed air to the closed spaces 2 and 8 via the pipe 5, and since the pressure of the compressed gas is stronger than the external atmospheric pressure, the compressed gas passes through the micropores of the microporous metal plate through the missile casing material to reach the multi-micropore missile shell. The outer surface. After the missile is launched, the gas in the enclosed space 8 has the same speed of motion as the missile. When it penetrates the outer surface of the missile casing, it also has the same speed of motion as the missile. On the outer surface of the missile casing, a missile with a moving object is formed. The gas layer of the same speed blocks the outside air from directly acting on the outer surface of the missile casing, thereby reducing or eliminating the resistance of the outside air to the high-speed motion missile, so that the missile can achieve higher flight speed.

Example 7

Different from Embodiment 6, the high-speed moving object of the present embodiment is an airplane, and the nose cone of the aircraft is made of a permeable metal plate.

Example 8

The difference from Example 1 is that the multi-microporous material of the present embodiment has a pore size of 200 μm.

Example 9

Different from Embodiment 1, the pores of the microporous material in the present embodiment have a stepped pore size distribution, the inner pore size is large, and is 100 micrometers; and the outer pore size is small, which is 3 micrometers.

Example 10

Different from the first embodiment, FIG. 3 is a schematic diagram of the head shell of the tractor of the high-speed train of the moving object of the present embodiment, where 1 is a carriage, 2 is a wheel, and 3 is a tractor head shell made of a ventilated metal plate. 4 is a moving direction indicating arrow, and 6 is a tractor head inner casing manufactured using a conventional dense non-porous metal plate, and a space between the inner casing 6 and the outer casing 3 is an enclosed space 5. The gas compressor delivers compressed air to the enclosed space 5 through a pipe (not shown). Since the pressure of the compressed gas is stronger than the external atmospheric pressure, the compressed gas can be transmitted from the micropores of the microporous metal plate 3 through the material of the front casing. The outer surface of the microporous outer shell. When the locomotive moves at high speed, the gas in the enclosed space 5 has the same moving speed as the locomotive. When it penetrates the outer surface of the locomotive casing, it also has the same moving speed as the locomotive, forming a movement and movement on the outer surface of the locomotive head casing. The gas layer of the same speed of the object locomotive blocks the outside air from directly acting on the outer surface of the locomotive casing, thereby reducing or eliminating the resistance of the outside air to the head of the high-speed moving locomotive, so that the locomotive can achieve a higher moving speed.

Example 11

Different from Embodiment 10, the moving object described in this embodiment is an automobile.

Example 12

Different from Embodiment 1, this embodiment generates ultrasonic vibration of the gas in the closed space and increases the transmission speed of the gas in the microporous material.

Example 13

Different from Embodiment 6, the gas source of the present embodiment is a gas generator or a built-in pressure vessel.

Example 14

The difference from Embodiment 1 is that the moving object in the embodiment is a torpedo, and the torpedo moves in the water. When the gas leaks out from the breathable metal shell of the torpedo, a mixed fluid layer of bubbles and water is formed between the water and the torpedo shell. To reduce the resistance of water to high-speed motion torpedoes, thereby increasing the speed of torpedo movement.

Example 15

Different from the embodiment 14, the underwater moving object in the embodiment is a submarine.

Example 16

Different from Embodiment 14, the object moving in water in this embodiment is a hydrofoil of a bubble boat or a hydrofoil.

In summary, the principle of the method of the present invention is as follows: for example, an air bearing, after the gas passes through the microporous material, a gas layer is formed on the surface of the microporous material, and the gas layer can withstand a certain external force. When the pore material moves at a high speed, the gas permeating from the microporous material has the same velocity as the microporous material, and if the velocity of the moving object is 100 m/sec, the gas permeating from the microporous material The speed is also 100 m / s, the gas oozing from the micro-porous material will vent the outside air, preventing the outside air from directly acting on the moving object, thereby reducing or eliminating the air resistance of the moving object, so that the moving object You can achieve higher speeds. When the object moves in the water, when the gas leaks out from the permeable shell of the moving object in the water, a mixed fluid layer of bubbles and water is formed between the water and the outer shell of the moving object, thereby reducing the resistance of the water to the high-speed moving object, thereby improving The speed of movement of moving objects in the water. The micro-porosity permeable metal shell can be manufactured by the metal fiber wire weaving, sintering and shaping process, and the pore size can be easily controlled. At the same time, the gas permeable metal material can maintain the structural shape of the moving object shell and meet the structural strength requirements.

The embodiments described above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, variations in the shapes and principles of the present invention are intended to be included within the scope of the present invention.

Claims

A method for manufacturing a gas permeable metal shell structure for reducing the resistance of a fluid to a moving object, characterized in that: first, a metal fiber yarn is woven to form a braid slab, and then sintered, and then the fiber strand sintered slab is pressed by plastic processing. Compressing the pore size of the sintered billet, reducing the porosity of the material, improving the mechanical properties of the material, while maintaining the pores of the material, obtaining a gas permeable fiber metal sheet; and then manufacturing the gas permeable metal sheet into a moving object shell by plastic pressure processing Shape and size, obtaining a permeable outer shell structure, one side of the multi-microporous permeable metal sheet material forms the outer surface of the moving object shell, and the other side forms the inner surface of the moving object shell, and constitutes a closed space; the gas source outputs pressure gas into the body In the enclosed space, gas permeates through the microporous permeable metal casing material from one side of the microporous permeable metal casing to the other surface of the microporous permeable metal casing, while the permeable metal material maintains the structural shape of the moving object casing and Meet structural strength requirements.
The metal fiber woven woven slab according to claim 1, wherein the metal fiber woven fabric is woven into a metal mesh cloth strip, and the metal mesh cloth strip is tightly wound to form a tight outer layer material. A layered clad slab body coated with an inner layer of material.
A metal fiber woven woven slab according to claim 1, wherein the metal fiber tow is woven into a woven plate body.
According to claim 1, a layer of powder is uniformly distributed on the fiber slab of the fiber, and the powder is rolled on the slab of the fiber slab, and then the powder layer is sintered to bond the powder to the fiber slab. And maintaining the pore communication between the powder particles, obtaining a gas permeable metal plate with pore size distribution along the thickness step, the pore size of the microporous gas permeable material is stepwisely distributed, the inner surface pore size is larger, and the outer surface pore size is smaller.
The outer casing of the moving object according to claim 1, wherein the outer casing is made of a gas permeable sheet having a plurality of micropores, and is a single layer shell structure.
The outer casing of the moving object according to claim 1, characterized in that it is a double-layered shell structure, the outer layer is made of a gas permeable sheet material having a plurality of micropores, and the inner layer is made of a dense non-porous metal structure sheet, the inner layer. There is a closed space between the outer layer and the air source and the closed space through the pipeline, and the pressurized gas can be input into the closed space through the pipeline.
When the moving object is moved at a high speed according to claim 1, the pressure gas is injected into the closed space from the gas source, so that the pressure of the gas in the closed space is stronger than the pressure of the external gas, and the pressure gas in the closed space passes through the micropores. The interconnected pores of the material penetrate through the shell of the microporous material to the outer surface of the shell of the microporous material to form a gas layer having the same velocity as the moving object, and block the external fluid from directly acting on the outer surface of the shell of the microporous material. Thereby reducing or eliminating the resistance of the external fluid to moving objects moving at high speed.
The enclosed space according to claim 1, wherein the sensor of the information collecting system is placed in the closed space, the pressure information of the closed space is collected, and the pressure information is sent to the control system, and the control system controls the valve on the pipeline. , control the on and off of the pipeline and the flow of gas and the pressure of the enclosed space.
A method of manufacturing a gas permeable metal casing structure for reducing the resistance of a fluid to a moving object according to claim 1, wherein the pressure gas in said enclosed space is subjected to ultrasonic vibration.
The invention relates to a method for manufacturing a gas permeable metal shell structure for reducing the resistance of a fluid to a moving object according to claim 1, characterized in that: a locomotive, a high speed train head, a car, an aircraft head, a projectile, a missile, a torpedo, Ships, submarines, and underwater vehicles are constructed into a permeable metal casing structure.