Device and method capable of achieving equivalent negative water depth and broadband water wave isolation

Abstract

The invention discloses a device and method capable of achieving equivalent negative water depth and broadband water wave isolation. The device comprises a plurality of gear structural parts which are arranged at equal intervals in a matrix mode. The gear structural part is a cylinder and comprises a first end and a second end, and two fan-shaped arc grooves which are in axial symmetry along the symmetric line of the bottom face are formed in the first bottom face of the first end. When the device is arranged on the water surface, the central axis of the cylinder of the gear structural part is perpendicular to the horizontal plane, the first end is exposed on the water surface, the fan-shaped arc groove is immersed in the water to a preset depth value, the second end is immersed in the water, and the equivalent water depth he and the equivalent propagation wave number ke of the device are both negative. The device has the advantages of being small in occupied area, simple in structure, low in cost, large in working range, capable of being suitable for complex water area environments, capable of blocking water waves and not blocking water flow and the like. Therefore, it is very necessary to invent the device to help people to better utilize resources on the sea.

Description

Technical Field

[0001] The present invention relates to the technical field of water wave isolation, and in particular to a device and method capable of realizing equivalent negative water depth and broadband water wave isolation. Background Art

[0002] The ocean has abundant resources and is an important place for human activities. However, the existence of tsunamis causes great harm to human activities and also poses a serious threat to marine operations. Since the wavelength of a tsunami is usually very long, generally up to tens of meters, traditional methods such as salt marshes, flood embankments and mangroves occupy a large area and are costly, which makes their practical application full of challenges. Therefore, how to conveniently and effectively isolate water waves is an important topic worthy of study in marine engineering, tsunami protection and water wave dynamics. Therefore, if a device can be invented that can achieve water wave isolation with a very small footprint and low cost, it will be very valuable for the protection of human marine operations and the protection of offshore buildings. At the same time, the device has a good wave isolation effect on various types of water waves in a wider range of water wave wavelengths, and has great application value for complex water environments in reality. Summary of the invention

[0003] In view of this, the purpose of the present invention is to propose a device and method that can achieve equivalent negative water depth and broadband water wave isolation, which has the advantages of small footprint, simple structure, low cost, large working range, applicability to complex water environment, blocking water waves without blocking water flow, etc. Therefore, it is very necessary to invent the device to help people make better use of marine resources.

[0004] According to one aspect of the present invention, there is provided a device capable of achieving equivalent negative water depth and broadband water wave isolation, comprising: a plurality of gear structural members arranged at equal intervals in a matrix;

[0005] The gear structure is a cylinder including a first end and a second end, and the first bottom surface of the first end is provided with two sector-shaped circular arc grooves symmetrical along the bottom surface symmetry line axis;

[0006] When the device is deployed on the water surface, the central axis of the cylindrical body of the gear structure is perpendicular to the horizontal plane, and the first end is exposed above the water, the fan-shaped arc groove is immersed in the water to a preset depth value, the second end is immersed in the water, and the equivalent water depth h of the device is satisfied. e is a negative number, the equivalent propagation wave number k e Is a pure imaginary number.

[0007] In the above technical solution, the device can effectively block water waves with a specific frequency and wavelength range, including plane waves and point sources, and can be applied to more complex water environments; the device occupies a small area, has a simple structure and is low in cost.

[0008] In some embodiments, the equivalent water depth h e and the equivalent propagation wave number k e The calculation formula is as follows:

[0009]

[0010] in,

[0011]

[0012] Where k0 is the wave number of water wave propagation; S is the geometric modulation factor; D n is the scattering coefficient of the gear structure, n represents the order, D n The whole represents the nth order scattering coefficient, n = 1, 2, 3, ..., N; h0 is the depth of the gear structure immersed in water; u e is the equivalent normalized water depth; u0 is the background normalized water depth; f s is the filling rate; i is an imaginary number; R2 is the outer arc radius of the fan-shaped arc groove; R3 is the radius of the equivalent water layer when the gear structure is surrounded by an equivalent water layer; J n and H n are n-order Bessel and Hankel functions representing the incident wave and scattered wave respectively; J′ n and H′ n is the derivative of the n-th order Hankel and Bessel functions; T(a, d, R2, n) is the structural transfer function; a is the distance between the center axes of two adjacent gear structural parts; d is the length of the semicircular arc of the bottom surface of the cylinder; n is the number of gears; L is the scattering modulation factor.

[0013] In the above technical solution, the amplitude expression of water waves propagating on a water surface can generally be written as:

[0014]

[0015] Where k0 is the propagation wave number in the r direction, k0 = 2π / λ, λ is the wavelength of the water wave. x is the propagation wave number in the x direction, k y is the propagation wave number in the y direction,

[0016] Find the required water depth and number of propagating waves to achieve complete isolation of water waves:

[0017] When the propagation wave number k0 is positive, the water wave amplitude expression is is a sinusoidal oscillation wave. At this time, the water wave can continue to propagate and the amplitude of the water wave will not decay. When the propagation wave number k0 is an imaginary number (k0 = ik1, k1 is a positive number), the water wave amplitude expression is It is a sinusoidal oscillation wave with a rapidly decaying amplitude. At this time, the amplitude of the water wave will quickly decay to 0 during the propagation process, and then the water wave disappears. Then we found the propagation wave number required to completely isolate the water wave, that is, to make the propagation wave number of the water wave become a pure imaginary number.

[0018] The corresponding relationship between the wave number and angular frequency of water wave propagation is as follows:

[0019]

[0020] Where ω is the angular frequency, g is the gravitational acceleration, and h is the water depth. Through calculation, it can be found that in order to achieve the pure imaginary propagation wave number k0, one of the gravitational acceleration g or the water depth h needs to be negative. Because the gravitational acceleration g is generally a positive constant and difficult to change, here we think about how to make the water depth h a negative number to achieve the pure imaginary propagation wave number k0. This part of the mechanism will be explained in the subsequent embodiments and will not be repeated here.

[0021] In some embodiments, the gear structure satisfies the following conditional formula:

[0022] 0.118

[0023] Where a is the distance between the center axes of two adjacent gear components; λ is the wavelength of the water wave.

[0024] In the above technical solution, based on the equivalent water depth h e and the equivalent propagation wave number k e The calculation formula and calculation process need to meet the prerequisite that the wavelength of the water wave λ is much larger than the gear structure interval a. After repeated calculations and optimizations, this case found that when a / λ=0.227, the water wave isolation effect is the best. At the same time, after calculations and experiments, it can be concluded that 0.118

[0025] In some embodiments, the gear structure satisfies the following conditional formula:

[0026] R1=0.05*a

[0027] R2=0.425*a

[0028] db=0.2*π*R2

[0029] b=0.8*d

[0030] Wherein, a is the distance between the center axes of two adjacent gear structural parts; R1 is the inner arc radius of the sector-shaped circular arc groove; R2 is the outer arc radius of the sector-shaped circular arc groove; d is the semicircular arc length of the bottom surface of the cylinder; b is the outer arc length of the sector-shaped circular arc groove.

[0031] In the above technical solution, based on the equivalent water depth h​​e and the equivalent propagation wave number k e Calculation formula. After repeated calculations and optimization, this case has obtained a simplified value formula for the size part. The above relationship can easily meet the equivalent water depth h of the device under the current size parameters. e is a negative number, the propagation wave number k e It is a pure imaginary number. At this time, after the water wave enters the periodic gear array device, the amplitude will decay rapidly until it is equal to 0, thus achieving a perfect water wave isolation effect.

[0032] In some embodiments, when the device is deployed on the water surface, the following conditional formula is satisfied:

[0033] h1=h0 / 14

[0034] L3>h0

[0035] Wherein, h0 is the depth of the gear structure immersed in water; h1 is the depth of the fan-shaped arc groove immersed in water; L3 is the height of the gear structure.

[0036] In the above technical solution, the above conditional formula is the optimal parameter obtained through calculation and experiment.

[0037] In some embodiments, when the device is deployed on the water surface, the fan-shaped arc grooves of a plurality of matrix-arranged tooth-shaped structural members have the same opening direction.

[0038] In the above technical solution, the opening direction of all gears must be the same. The basis for calculating the equivalent parameters of this device in this case is to require that all gears are exactly the same, so the opening must be the same. If the opening is different, the effect will be worse. The opening direction here needs to be the same

[0039] In some embodiments, the gear structure is made of rigid material.

[0040] In the above technical solution, in the selection of materials for structural parts, priority is given to rigid bodies that are impermeable and not prone to deformation. At the same time, the device density should preferably be able to make the device sink into water, such as metal materials such as stainless steel. However, in actual applications, concrete is more recommended due to its lower cost.

[0041] In some embodiments, the gear structure is made of a plastic material with a density lower than that of water, and when the device is deployed on the water surface, each gear structure is fixed by a fixing device.

[0042] In the above technical solution, as an optional example, in the selection of materials for the structural parts, a rigid material with a density less than that of water, such as plastic, etc., can also be used. In this case, the device needs to be fixed in water. The fixing method can be to insert it into the bottom of the water, or to fix it to the bottom of the water with a heavier chassis.

[0043] According to another aspect of the present invention, a design method for realizing equivalent negative water depth and broadband water wave isolation is provided. Based on the above-mentioned device for realizing equivalent negative water depth and broadband water wave isolation, the method comprises the following steps:

[0044] The equivalent water depth h of the device is e is a negative number, the equivalent propagation wave number k e Under the premise that the distance a between the center axes of two adjacent gear structures of the device is a negative number, the optimal solution of the radius of the outer arc R2 and inner arc R1 of the fan-shaped circular arc groove of each gear structure, the semicircular arc length d of the bottom surface of the cylinder, and the outer arc length of the fan-shaped circular arc groove is determined;

[0045] Based on the optimal solution, several gear structures are prepared and arranged in a matrix with equal spacing on the water surface in the area where water waves need to be isolated; and,

[0046] When the device is deployed on the water surface, the central axis of the cylindrical body of the gear structure is perpendicular to the horizontal plane, and the first end is exposed above the water, the fan-shaped arc groove is immersed in the water to a preset depth value, and the second end is immersed in the water.

[0047] In the above technical solution, the present invention proposes a design method for realizing this function, and the method has certain scalability and flexibility, and can design a variety of periodic gear array devices that meet the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 This is one of the schematic diagrams of the device layout structure of an embodiment of a device capable of achieving equivalent negative water depth and broadband water wave isolation according to the present invention;

[0050] Figure 2 It is a schematic diagram of a gear structure of an embodiment of a device for realizing equivalent negative water depth and broadband water wave isolation of the present invention; in the figure, ① is a schematic diagram of a three-dimensional structure, and ② is a schematic diagram of a structure from a side view of A;

[0051] Figure 3 This is the second schematic diagram of the device layout structure of an embodiment of a device capable of achieving equivalent negative water depth and broadband water wave isolation according to the present invention;

[0052] Figure 4It is a flow chart of an embodiment of a design method for realizing equivalent negative water depth and broadband water wave isolation according to the present invention. DETAILED DESCRIPTION

[0053] The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention. Similarly, the following examples are only partial embodiments of the present invention rather than all embodiments, and all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0054] The present invention provides a device and method for realizing equivalent negative water depth and broadband water wave isolation, and the device has the advantages of small footprint, simple structure, low cost, large working range, applicable to complex water environment, blocking water waves without blocking water flow, etc. Therefore, it is very necessary to invent the device to help people make better use of marine resources.

[0055] Embodiment 1

[0056] See also Figure 1 , a device capable of realizing equivalent negative water depth and broadband water wave isolation, comprising: a plurality of gear structural members 1 arranged at equal intervals in a matrix;

[0057] See also Figure 2 The gear structure 1 is a cylinder, including a first end A and a second end B. The first bottom surface of the first end A is provided with two fan-shaped arc grooves 11 symmetrical along the bottom symmetry line axis and a gear structure 12 formed based on the groove body; the first end and the second end are connected, and the interval of the first end is determined by the interval of the second end, and the interval of the second end can be determined by the interval of the insertion into the ground, or by the interval of the installation base. This immersion depth requires that the first end must be immersed in water, and try to ensure that h1 = h0 / 14.

[0058] See also Figure 3 When the device is placed on the water surface, the central axis of the cylindrical body of the gear structure 1 is perpendicular to the horizontal plane, and the first end A is exposed to the water, the fan-shaped arc groove 11 is immersed in the water to a preset depth value h1, and the second end B is immersed in the water, and the equivalent water depth h of the device is satisfied. e is a negative number, the equivalent propagation wave number k e Is a negative number.

[0059] In this embodiment, the device can effectively block water waves with a specific frequency and wavelength range, including plane waves and point sources, and can be applied to more complex water environments; the device occupies a small area, has a simple structure and is low cost.

[0060] In this embodiment, when the device is deployed on the water surface, the following conditional formula is satisfied:

[0061] h1=h0 / 14

[0062] L1=W

[0063] L2=4a

[0064] L3>h0

[0065] Wherein, h0 is the depth of the gear structure immersed in water; h1 is the depth of the fan-shaped arc groove immersed in water; L1 is the length of the device coverage surface, W is the width of the area isolating water waves; L2 is the width of the device coverage surface; a is the distance between the two gear structures; L3 is the height of the gear structure.

[0066] In this embodiment, the equivalent water depth h e and the equivalent propagation wave number k e The calculation formula is as follows:

[0067]

[0068] in,

[0069]

[0070] Where k0 is the wave number of water wave propagation; S is the scattering modulation factor; D n is the scattering coefficient of the gear structure, n represents the order, D n The whole represents the nth order scattering coefficient, n = 1, 2, 3, ..., N; h0 is the depth of the gear structure immersed in water; u e is the equivalent normalized water depth; u0 is the background normalized water depth; f s is the filling rate; i is an imaginary number; R2 is the outer arc radius of the fan-shaped arc groove; R3 is the radius of the equivalent water layer when the gear structure is surrounded by an equivalent water layer; J n and H n are n-order Bessel and Hankel functions representing the incident wave and scattered wave respectively; J′ n and H′ n is the derivative of the n-th order Hankel and Bessel functions; T(a, d, R2, n) is the structural transfer function; a is the distance between the center axes of two adjacent gear structural parts; d is the length of the semicircular arc of the bottom surface of the cylinder; n is the number of gears; L is the scattering modulation factor.

[0071] In general, the amplitude expression of water waves propagating on a water surface can be written as:

[0072]

[0073] Where k0 is the propagation wave number in the r direction, k0 = 2π / λ, λ is the wavelength of the water wave. x is the propagation wave number in the x direction, k y is the propagation wave number in the y direction,

[0074] Find the required water depth and number of propagating waves to achieve complete isolation of water waves:

[0075] When the propagation wave number k0 is positive, the water wave amplitude expression is is a sinusoidal oscillation wave. At this time, the water wave can continue to propagate and the amplitude of the water wave will not decay. When the propagation wave number k0 is an imaginary number (k0 = ik1, k1 is a positive number), the water wave amplitude expression is It is a sinusoidal oscillation wave with a rapidly decaying amplitude. At this time, the amplitude of the water wave will quickly decay to 0 during the propagation process, and then the water wave disappears. Then we found the propagation wave number required to completely isolate the water wave, that is, to make the propagation wave number of the water wave become a pure imaginary number.

[0076] The corresponding relationship between the wave number and angular frequency of water wave propagation is as follows:

[0077]

[0078] Among them, ω is the angular frequency, g is the gravitational acceleration, and h is the water depth. Through calculation, it can be found that in order to achieve the pure imaginary propagation wave number k0, one of the gravitational acceleration g or the water depth h needs to be negative. Because the gravitational acceleration g is generally a positive constant and difficult to change, here we think about how to make the water depth h a negative number to achieve the pure imaginary propagation wave number k0.

[0079] Determine the conditions required to achieve negative water depth and wave isolation; specifically include the following:

[0080] This embodiment designs a wave isolation device that can achieve equivalent negative water depth and broadband water waves. Figures 1 to 3 , the equivalent negative water depth h can be achieved, thereby changing the wave number k0 of the water wave propagation into a pure imaginary number, so that the amplitude of the water wave quickly decays to 0, thereby achieving perfect water wave isolation. We calculated through the coherent potential approximation method that its shape is a periodic gear array. Specifically, the entire device includes 4 rows of evenly arranged gear structure bodies (experiments have shown that as long as there are more than 2 rows, the effect is very good. When there are 4 rows, the water waves can be completely isolated. The more rows, the better the effect.) The body length is L1, the width is L2, and the height is L3. The interval between every two gears is a. Each gear structure has 2 teeth, which are symmetrically distributed on the left and right. The inner diameter is R1 and the outer diameter is R2. The corresponding arc length is db, so each gear structure has 2 grooves, which are symmetrically distributed on the top and bottom. The inner diameter is R1 and the outer diameter is R2. The corresponding arc length is b.

[0081] Then, based on the above device, the water depth applicable to the device is determined. When the main body is immersed in water, the top of the main body is above the water surface, the water depth of the bottom surface of the main body is h0, and the water depth of the groove of each gear structure is h1. The length L1 of the main body is equal to the width of the area where water waves need to be isolated. The width L2 of the main body is generally the width of 4 rows of gears, that is, L2=4a. The height L3 of the main body is adjusted according to the water depth of the use area, and L3 is greater than the water depth h0. The water depth h1 of the groove of each gear structure is generally one-fourteenth of the water depth h0 of the area, that is, h1=h0 / 14.

[0082] After completing the above steps, the equivalent negative water depth and wave isolation function parameters of the periodic gear array device are determined. The function parameters include the equivalent water depth h of the periodic gear array device e ; Equivalent propagation wave number k of periodic gear array device e The details are as follows:

[0083] First, the relationship between the functional parameters and the device structural parameters is determined as follows: The equivalent water depth h of the periodic gear array device e and propagation wave number k e The relationship between the spacing a, inner diameter R1, outer diameter R2, and corresponding arc length db of the gear structure, and the inner diameter R1, outer diameter R2, and corresponding arc length b of the gear groove is as follows:

[0084]

[0085] in

[0086]

[0087] The calculation process is as follows:

[0088] For the convenience of calculation, we put the origin of the coordinates at Figure 1 We assume that the gear is surrounded by an equivalent water layer. The corresponding parameter is the equivalent water depth h e and the equivalent propagation wave number k e .

[0089] The water wave amplitude η in region 2 (R2≤r≤R3) and region 3 (r≥R3) can be written as:

[0090] η2=∑ n [B n J n (k0r)+C n H n (k0r)]e inθ (R2≤r≤R3)

[0091] η3=∑n [E n J n (k e r)+F n H n (k e r)]e inθ (r≥R3)

[0092] where J n and H n are the nth-order Bessel and Hankel functions representing the incident wave and the scattered wave respectively. The amplitude of the water wave needs to satisfy the hydrostatic pressure p = ρgη and the flux continuity (where ρ is the fluid density, g is the acceleration due to gravity, u is the normalized water depth, ω is the angular frequency, is the gradient operator) at the boundaries of different regions. Since we assume that region 3 (r > R3) is an equivalent water layer, there should be no scattering at the boundary between regions 2 and 3, that is, F n = 0. So we can get:

[0093]

[0094] where D n is the scattering coefficient of the gear, T n (u e , k e , R3) = k e u e J′ n (k e R3) / J n (k e R3).

[0095] By simplification, the equivalent water depth h e and the propagation wave number k e of the periodic gear array device can be obtained:

[0096]

[0097] where

[0098] This is the above equation (3).

[0099] Then we write the expressions for the water wave amplitudes in regions 1 (R1 << r << R2) and 2 (R2 << r << R3):

[0100]

[0101] η2 = ∑ n [B n J n (k0r)+Cn H n (k0r)]e inθ (R2≤r≤R3)

[0102] The propagation wave number k1 in area 1 and the propagation wave number k0 in area 2 need to satisfy the following relationship:

[0103] k1*tanh(k1h1)=k0*tanh(k0h0)

[0104] Among them, H 1 and H 2 are functions of the first and second kind, representing the scattered waves propagating outward and the incident waves propagating inward, respectively. Similarly, the amplitude of water waves at the boundaries of different regions needs to satisfy both the hydrostatic pressure p = ρgη and the flux Continuous, so we can get:

[0105]

[0106] where T(b,d,R2,n)=dsinc(dn / R2 / 2) / [bsinc(bn / R2 / 2)],

[0107] This is the above equation (4).

[0108] Finally, by combining equations (3) and (4), the equivalent water depth h of the periodic gear array device can be calculated. e and propagation wave number k e After completing the above steps, the device design parameters can be output. Specifically, the following steps are included: by using the periodic gear array device to achieve the water depth and propagation wave number required for perfect water wave isolation, the interval a between each two gear structures of the device, as well as the inner diameter R1, outer diameter R2 of the teeth and grooves of each gear structure, and the optimal solution of their corresponding arc lengths db and b are calculated.

[0109] In this embodiment, as an optional example, the gear structure satisfies the following conditional formula:

[0110] 0.118

[0111] In the formula, a is the distance between the center axes of two adjacent gear components; λ is the wavelength of the water wave. According to the calculation process of the above formulas (1)-(7), it is necessary to satisfy that the wavelength of the water wave λ is much larger than the gear structure spacing a. After repeated calculations and optimizations, it is found that when a / λ=0.227, the water wave isolation effect is the best. At the same time, after calculations and experiments, it can be found that 0.118

[0112] ​​In this embodiment, as an optional example, the gear structure satisfies the following conditional formula:

[0113] R1=0.05*a

[0114] R2=0.425*a

[0115] db=0.2*π*R2

[0116] b=0.8*d

[0117] In the formula, a is the distance between the center axes of two adjacent gear components; R1 is the inner arc radius of the sector arc groove; R2 is the outer arc radius of the sector arc groove; d is the semicircular arc length of the bottom surface of the cylinder; b is the outer arc length of the sector arc groove. Take the inner diameter R1 = 0.05*a, the outer diameter R2 = 0.425*a of the gear structure's teeth and grooves, and their corresponding arc lengths are: db = 0.2*π*R2, b = 0.8*d. Finally, these parameters are substituted into the equivalent water depth h in formula (3): e and propagation wave number k e From the expression of e is a negative number, the propagation wave number k e It is a pure imaginary number. At this time, after the water wave enters the periodic gear array device, the amplitude will decay rapidly until it is equal to 0, thus achieving a perfect water wave isolation effect.

[0118] In this embodiment, when the device is deployed on the water surface, the fan-shaped arc grooves of the plurality of tooth-shaped structural members arranged in a matrix have the same opening direction.

[0119] In this embodiment, as an optional example, the gear structure is made of a rigid material. As an optional example, in the selection of materials for the structure, a rigid body that is impermeable and not easily deformed is preferably selected, and the device density is preferably such that the device can sink into water, such as various rigid metals.

[0120] In this embodiment, as an optional example, the gear structure is made of a plastic material with a density less than water, and when the device is deployed on the water surface, each gear structure is fixed by a fixing device. As an optional example, in the selection of materials for the structure, a rigid material with a density less than water, such as plastic, can also be used, in which case the device needs to be fixed in the water.

[0121] In a 1300cm×90cm rectangular pool, a wave-making device is placed at the left end to generate plane waves with a frequency of 0 to 2Hz and an amplitude of 1 to 10cm. An inclined sponge is placed at the right end to absorb water waves and reduce their reflection, which can simulate the propagation of water waves in rivers in nature. Then the length of the periodic gear array device is L1 = 90cm, the width is L2 = 90cm, the interval between each two gear structures is a = 22.35cm, each gear structure has 2 teeth, which are symmetrically distributed on the left and right, and its inner diameter is R1 = 0.05*a = 1.12cm, and its outer diameter is R2 = 0.425*a = 9.5cm. The corresponding arc length db = 0.2*π*R2 = 4.48cm, so each gear structure has 2 grooves, which are symmetrically distributed up and down, and its inner diameter is R1 = 0.05*a = 1.12cm, and its outer diameter is R2 = 0.425*a = 9.5cm. The corresponding arc length is b = 0.8*π*R2 = 25.37cm, as shown in Figure 2 As shown:

[0122] The height of the periodic gear array device is L3 = 30 cm. When the periodic gear array device is immersed in water, the top of the periodic structure is above the water surface. The water surface below the periodic gear array device is h0, h0 = 21 cm, and the water depth at each gear groove is h1 = h0 / 14 = 1.43 cm. Figure 3 As shown:

[0123] Here we set the type of water wave to plane wave, the frequency f of the water wave is 1.17Hz, the corresponding wavelength λ=98.47cm, the relationship with the gear spacing a is a / λ=0.227, and the amplitude of the water wave is 10mm. We use a water wave amplitude sensor to measure the amplitude of the water waves on the left and right ends of the periodic gear array device to test the wave isolation performance of the periodic gear array device. The water wave is incident from the left side of the rectangular pool. When the water wave encounters the periodic gear array device, it is strongly reflected, and the water wave cannot penetrate the periodic gear array device at all. The results of the water wave amplitude sensor show that the amplitude of the water wave on the left side of the periodic gear array device is 15.23mm, and the amplitude of the water wave on the right side is almost 0, proving that the periodic gear array device has very good wave isolation performance.

[0124] In order to more clearly demonstrate the wave-isolating performance of the periodic gear array device, we placed two small boats on both sides of the periodic gear array. When water waves were incident from the left, it can be seen that the small boat on the left side of the periodic gear array device vibrated violently because the water waves were blocked on the left side of the periodic gear array device. However, because the water waves could not penetrate the periodic gear array device, the small boat on the right side of the periodic gear array device remained motionless. This also indirectly proves the excellent wave-isolating performance of the periodic gear array device.

[0125] At the same time, in order to test the wave isolation performance of the periodic gear array device in complex water environments, we also conducted tests under different wave sources and different frequencies. The results are as follows:

[0126] Different wave sources: We changed the type of water waves from plane waves to point sources radiating in all directions. The water wave frequency, wavelength and various parameters of the periodic gear array device remained unchanged. The experimental results showed that point source water waves radiating in all directions could not pass through the periodic gear array device. The device also had excellent wave isolation effect for point source water waves.

[0127] Different frequencies: We reduced the frequency of the above-mentioned test water waves from 1.17Hz to 0.7Hz~1.4Hz. The water wave types include plane waves and point sources. The experimental results show that the water wave isolation rate of the periodic gear device in the range of 0.7Hz~1.0Hz is as high as over 90%, and the water wave isolation rate in the range of 1.0~1.4Hz is over 99%. Therefore, the periodic gear array device has excellent water wave isolation effect in a wider frequency.

[0128] The advantages of the present invention are:

[0129] (1) After design, the device can effectively block water waves with a specific frequency and wavelength range, including plane waves and point sources, and can be applied to more complex water environments; (2) The device occupies a small area, has a simple structure and low cost; (3) A design method to achieve this function is proposed, and the method has certain scalability and flexibility, and can be used to design a variety of periodic gear array devices that meet the requirements.

[0130] Embodiment 2

[0131] See also Figure 4 , a design method capable of realizing equivalent negative water depth and broadband water wave isolation, based on a device capable of realizing equivalent negative water depth and broadband water wave isolation as described in one of the embodiments, the method comprises the following steps:

[0132] S1, equivalent water depth h of the device e is a negative number, the equivalent propagation wave number k e Under the premise that the distance a between the center axes of two adjacent gear structures of the device is a negative number, the optimal solution of the radius of the outer arc R2 and inner arc R1 of the fan-shaped circular arc groove of each gear structure, the semicircular arc length d of the bottom surface of the cylinder, and the outer arc length of the fan-shaped circular arc groove is determined;

[0133] S2. Based on the optimal solution, a number of gear structures are prepared and arranged in a matrix with equal spacing on the water surface in the area where water waves need to be isolated; and

[0134] S3. When the device is deployed on the water surface, the central axis of the cylindrical body of the gear structure is perpendicular to the horizontal plane, and the first end is exposed above the water, the fan-shaped arc groove is immersed in the water to a preset depth value, and the second end is immersed in the water.

[0135] In the above technical solution, the present invention proposes a design method for realizing this function, and the method has certain scalability and flexibility, and can design a variety of periodic gear array devices that meet the requirements. The specific principle and detailed introduction of the device can be found above, and will not be repeated here.

[0136] The above descriptions are only some embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any equivalent device or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device capable of achieving equivalent negative water depth and broadband water wave isolation, characterized in that: It includes a plurality of gear structural parts arranged at equal intervals in a matrix; The gear structure is a cylinder including a first end and a second end, and the first bottom surface of the first end is provided with two sector-shaped circular arc grooves symmetrical along the bottom surface symmetry line axis; When the device is deployed on the water surface, the central axis of the cylindrical body of the gear structure is perpendicular to the horizontal plane, and the first end is exposed above the water, the fan-shaped arc groove is immersed in the water to a preset depth value, the second end is immersed in the water, and the equivalent water depth h of the device is satisfied. e is a negative number, the equivalent propagation wave number k e Is a negative number.

2. A device capable of realizing equivalent negative water depth and broadband water wave isolation as claimed in claim 1, characterized in that: The equivalent water depth h e and the equivalent propagation wave number k e The calculation formula is as follows: in, Where k0 is the wave number of water wave propagation; S is the geometric modulation factor; D n is the scattering coefficient of the gear structure, n represents the order, D n The whole represents the nth order scattering coefficient, n = 1, 2, 3, ..., N; h0 is the depth of the gear structure immersed in water; u e is the equivalent normalized water depth; u0 is the background normalized water depth; f s is the filling rate; i is an imaginary number; R2 is the outer arc radius of the fan-shaped arc groove; R3 is the radius of the equivalent water layer when the gear structure is surrounded by an equivalent water layer; J n and H n are n-order Bessel and Hankel functions representing the incident wave and scattered wave respectively; J′ n and H′ n is the derivative of the n-th order Hankel and Bessel functions; T(a, d, R2, n) is the structural transfer function; a is the distance between the center axes of two adjacent gear structural parts; d is the length of the semicircular arc of the bottom surface of the cylinder; n is the number of gears; L is the scattering correction factor.

3. A device capable of achieving equivalent negative water depth and broadband water wave isolation as claimed in claim 1 or 2, characterized in that: The gear structure satisfies the following conditional formula: In the formula (0.118), a is the distance between the center axes of two adjacent gear structural members; λ is the wavelength of the water wave.

4. A device capable of achieving equivalent negative water depth and broadband water wave isolation as claimed in claim 3, characterized in that: The gear structure satisfies the following conditional formula: R1=0.05*a R2=0.425*a db=0.2*π*R2 b=0.8*d Wherein, a is the distance between the center axes of two adjacent gear structural parts; R1 is the inner arc radius of the sector-shaped circular arc groove; R2 is the outer arc radius of the sector-shaped circular arc groove; d is the semicircular arc length of the bottom surface of the cylinder; b is the outer arc length of the sector-shaped circular arc groove.

5. A device capable of achieving equivalent negative water depth and broadband water wave isolation as claimed in claim 1 or 2, characterized in that: When the device is deployed on the water surface, the following conditions are met: h1=h0 / 14 L3>h0 Wherein, h0 is the depth of the gear structure immersed in water; h1 is the depth of the fan-shaped arc groove immersed in water; L3 is the height of the gear structure.

6. The device capable of realizing equivalent negative water depth and broadband water wave isolation as claimed in claim 1, characterized in that: When the device is arranged on the water surface, the fan-shaped arc grooves of the plurality of tooth-shaped structural members arranged in a matrix have the same opening direction.

7. The device capable of realizing equivalent negative water depth and broadband water wave isolation as claimed in claim 1, characterized in that: The gear structure is made of rigid material.

8. The device capable of realizing equivalent negative water depth and broadband water wave isolation as claimed in claim 1, characterized in that: The gear structure is made of a plastic material with a density lower than that of water, and when the device is arranged on the water surface, each gear structure is fixed by a fixing device. Based on the device capable of realizing equivalent negative water depth and broadband water wave isolation according to any one of claims 1 to 8, the method comprises the following steps:

9. A design method for achieving equivalent negative water depth and broadband water wave isolation, characterized in that: Based on the optimal solution, several gear structures are prepared and arranged in a matrix with equal spacing on the water surface in the area where water waves need to be isolated; and, The equivalent water depth h of the device is e is a negative number, the equivalent propagation wave number k e Under the premise that the distance a between the center axes of two adjacent gear structures of the device is a negative number, the optimal solution of the radius of the outer arc R2 and inner arc R1 of the fan-shaped circular arc groove of each gear structure, the semicircular arc length d of the bottom surface of the cylinder, and the outer arc length of the fan-shaped circular arc groove is determined; When the device is deployed on the water surface, the central axis of the cylindrical body of the gear structure is perpendicular to the horizontal plane, and the first end is exposed above the water, the fan-shaped arc groove is immersed in the water to a preset depth value, and the second end is immersed in the water. ​

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