CN108831433B - Acoustic super-surface and acoustic vortex wave generator - Google Patents
Acoustic super-surface and acoustic vortex wave generator Download PDFInfo
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- CN108831433B CN108831433B CN201810898025.6A CN201810898025A CN108831433B CN 108831433 B CN108831433 B CN 108831433B CN 201810898025 A CN201810898025 A CN 201810898025A CN 108831433 B CN108831433 B CN 108831433B
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/18—Methods or devices for transmitting, conducting or directing sound
- G10K11/26—Sound-focusing or directing, e.g. scanning
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/36—Devices for manipulating acoustic surface waves
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
According to the acoustic super-surface, through the cylindrical cavity structure, the phase units of the at least 4 fan-shaped cylinder structures are surrounded by the central shaft of the cylindrical cavity structure, meanwhile, the at least 4 phase units are annularly arranged on 0 to 2 pi in a phase gradient increasing mode, so that the effect that when incident sound waves enter the acoustic super-surface, the acoustic super-surface is provided with the phased array annularly arranged around the propagation direction is achieved, and the acoustic super-surface is simple in structure. The embodiment of the application also discloses an acoustic vortex wave generator, which realizes the conversion from an acoustic plane wave to an acoustic vortex wave and realizes the regulation and control of the acoustic wave phase.
Description
Technical Field
The invention relates to the technical field of ultrasonic waves, in particular to an acoustic super-surface and an acoustic vortex wave generator.
Background
Metamaterials are artificial composite structures or composite materials with unusual physical properties that natural materials do not possess, and in nature, vortex phenomena that carry angular momentum, such as water vortex and cyclone, are very common. The acoustic vortex is similar to the optical vortex. The phenomenon that the sound wave is spirally twisted due to the phase singularity in the propagation process and the sound intensity on the central axis is zero is called sound vortex.
At present, an active acoustic super-surface resonance principle is adopted to generate the acoustic vortex wave, but the existing structure model is complex in structure, the generated effect is not obvious enough, and the structural property of the device is not stable enough.
Disclosure of Invention
The embodiment of the application provides an acoustic super-surface and an acoustic vortex wave generator, which realize that a phased array which is annularly arranged around the propagation direction is generated after an incident sound wave enters the acoustic vortex wave generator, and the acoustic super-surface and acoustic vortex wave generator has a simple structure.
The embodiment of the application provides an acoustic super-surface and acoustic vortex wave generator, which is of a cylindrical cavity structure;
the cylindrical cavity structure includes:
at least 4 phase units, each phase unit is a sector cylinder, and the at least 4 sector cylinders enclose a cylindrical cavity structure based on a central shaft of the cylindrical cavity structure;
at least 4 of the phase cells are arranged in a circular line over 0 to 2 pi in a phase gradient increasing manner.
Optionally, the side view two-dimensional pattern of the phase unit is an axisymmetric pattern;
the height h and the width l of each phase unit are consistent, and every two adjacent phase units are connected through a solid plate;
the shape of the side view two-dimensional pattern of each phase cell is generally in the shape of a bracket formed by left and right boundaries inside which is at least one rectangle corresponding to a diaphragm for generating a deflection phase.
Optionally, the number of the phase units is 6, and specifically includes: a first phase unit, a second phase unit, a third phase unit, a fourth phase unit, a fifth phase unit, and a sixth phase unit;
the deflection phase generated by the first phase unit is 0-5 degrees, the deflection phase generated by the second phase unit is 60-65 degrees, the deflection phase generated by the third phase unit is 120-126 degrees, the deflection phase generated by the fourth phase unit is 176-180 degrees, the deflection phase generated by the fifth phase unit is 233-240 degrees, and the deflection phase generated by the sixth phase unit is 297-300 degrees.
Optionally, the wavelength of the incident wave incident into the acoustic super surface is λ.
Optionally, the thicknesses l of the rectangles corresponding to all diaphragms of the first and second phase units 0 And width l 1 Are all corresponding and consistent;
all diaphragms of the third, fourth, fifth and sixth phase unitsWidth l of rectangle corresponding to the plate 1 Is the width l of the rectangle corresponding to the diaphragm plate of the first phase unit and the second phase unit 1 Half of (a) is provided.
Optionally, the lengths of the top and bottom edges of the left and right boundaries of the first phase element are a first w 1 ＝0.14λ～0.15λ；
The thickness of the top and bottom edges of the left and right boundaries of the first phase element is first h 1 ＝0.057λ～0.059λ；
Thickness of the boundary of the left and right boundaries of the first phase unit is a first w 2 ＝0.01λ～0.04λ。
Optionally, the lengths of the top and bottom edges of the left and right boundaries of the second phase unit are a second w 1 ＝0.19λ～0.21λ；
The thickness of the top and bottom edges of the left and right boundaries of the second phase unit is second h 1 ＝0.057λ～0.059λ；
Thickness of the boundary of the left boundary and the right boundary of the second phase unit is second w 2 ＝0.01λ～0.04λ。
Optionally, the lengths of the top and bottom edges of the left and right boundaries of the third phase unit are third w 1 ＝0.125λ～0.145λ；
The thickness of the top and bottom edges of the left and right boundaries of the third phase unit is third h 1 ＝0.108λ～0.115λ；
Thickness third w of the boundaries of the left and right boundaries of the third phase unit 2 ＝0.01λ～0.04λ；
The third phase unit comprises 2 diaphragms.
Optionally, the lengths of the top and bottom edges of the left and right boundaries of the fourth phase element are fourth w 1 ＝0.15λ～0.175λ；
The thickness of the top and bottom edges of the left and right boundaries of the fourth phase element is fourth h 1 ＝0.108λ～0.11λ；
Thickness of the boundary of the left boundary and the right boundary of the fourth phase cell is fourth w 2 ＝0.01λ～0.04λ；
The fourth phase unit comprises 2 diaphragms.
Optionally, the lengths of the top and bottom edges of the left and right boundaries of the fifth phase element are fifth w 1 ＝0.175λ～0.185；
Thickness fifth h of top and bottom edges of left and right boundaries of the fifth phase unit 1 ＝0.108λ～0.11λ；
Thickness fifth w of the boundaries of the left and right boundaries of the fifth phase unit 2 ＝0.01λ～0.04λ；
The fifth phase unit comprises 2 diaphragms.
Alternatively, the process may be carried out in a single-stage,
lengths of top and bottom edges of left and right boundaries of the sixth phase element, sixth w 1 ＝0.18λ～0.20λ；
Thickness sixth h of top and bottom edges of left and right boundaries of sixth phase cell 1 ＝0.0285λ～0.029λ；
Thickness sixth w of the boundaries of the left and right boundaries of the sixth phase cell 2 ＝0.02λ～0.04λ；
The sixth phase unit comprises 3 diaphragms.
From the above technical solutions, the embodiments of the present application have the following advantages:
according to the acoustic super-surface, through the cylindrical cavity structure, the phase units of the at least 4 fan-shaped cylinder structures are surrounded by the central shaft of the cylindrical cavity structure, meanwhile, the at least 4 phase units are annularly arranged on 0 to 2 pi in a phase gradient increasing mode, so that the effect that when incident sound waves enter the acoustic super-surface, the acoustic super-surface is provided with the phased array annularly arranged around the propagation direction is achieved, and the acoustic super-surface is simple in structure.
The embodiment of the application also discloses an acoustic vortex wave generator, which realizes the conversion from an acoustic plane wave to an acoustic vortex wave and realizes the regulation and control of the acoustic wave phase.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic side view of a phase element of an acoustic subsurface according to an embodiment of the present application;
FIGS. 2 (a) and 2 (b) are a schematic side view two-dimensional diagram and a corresponding three-dimensional diagram of a first phase unit of an acoustic subsurface provided in an embodiment of the present application;
FIGS. 3 (a) and 3 (b) are a side two-dimensional schematic and corresponding three-dimensional diagram of a second phase element of an acoustic subsurface provided in an embodiment of the present application;
FIGS. 4 (a) and 4 (b) are a side two-dimensional schematic and a corresponding three-dimensional diagram of a third phase unit of an acoustic subsurface provided in an embodiment of the present application;
FIGS. 5 (a) and 5 (b) are a side two-dimensional schematic and a corresponding three-dimensional diagram of a fourth phase element of an acoustic subsurface provided in an embodiment of the present application;
FIGS. 6 (a) and 6 (b) are a side two-dimensional schematic and a corresponding three-dimensional diagram of a fifth phase element of an acoustic subsurface provided in an embodiment of the present application;
FIGS. 7 (a) and 7 (b) are a side two-dimensional schematic and a corresponding three-dimensional diagram of a sixth phase element of an acoustic subsurface provided in an embodiment of the present application;
FIG. 8 is a schematic diagram of acoustic wave propagation;
FIG. 9 is a schematic diagram of an overall model of an acoustic vortex wave generator provided in an embodiment of the present application before simulation;
FIG. 10 is a deflection phase diagram of 6 phase cells of an acoustic subsurface of an embodiment of the present application;
FIG. 11 (a) is a simulated acoustic pressure surface plot of an acoustic vortex wave generator according to an embodiment of the present application;
FIG. 11 (b) is a cross-sectional view of an post-simulation exit air column of an acoustic vortex wave generator in accordance with an embodiment of the present application;
FIG. 11 (c) is an absolute sound pressure plot of a simulated cross-sectional view of an acoustic vortex wave generator according to an embodiment of the present application;
FIG. 12 is a cross-sectional view of an exit air column from far to near after simulation of an acoustic vortex wave generator in accordance with an embodiment of the present application;
FIG. 13 is a graph of transmittance of a simulated acoustic vortex wave generator according to the present embodiment with the ability to convert plane waves into vortex waves as the incident frequency changes;
FIG. 14 is a simulation structure diagram of the incident sound wave of the sound vortex wave generator in the embodiment of the application with the frequency of 0.35MHz, 0.37MHz, 0.39MHz and 0.41 MHz;
FIG. 15 is a graph showing the projection ratio of the ultrasonic vortex wave generator according to the embodiment of the present application under different incident sound wave frequencies under the condition that plane waves can be converted into revolve vortex wave fronts when the fillers in the ultrasonic vortex wave generator are air and CO2, respectively;
fig. 16 (a) is a diagram of an acoustic vortex wave generated by an acoustic vortex wave generator at an incident acoustic wave of f=0.5 MHz;
fig. 16 (b) is a phase diagram of fig. 16 (a);
fig. 17 (a) is a diagram of an acoustic vortex wave generated by clockwise twisting the acoustic vortex wave generator of fig. 16 (a) by 30 ° at an incident acoustic wave of f=0.5 MHz;
fig. 17 (b) is a phase diagram of fig. 17 (a);
FIG. 18 is a schematic view of the angle of clockwise twist of the acoustic vortex wave generator with the phase deflected counter-clockwise;
FIG. 19 is a schematic diagram showing counterclockwise deflection of the acoustic vortex generator filler with different angles of phase at different temperatures with air;
FIG. 20 is a schematic diagram of the phase deflection of the acoustic vortex generator occurring at different temperatures of the filler air;
FIG. 21 (a) is a schematic diagram of two acoustic vortex generators at an incident acoustic wave frequency of 0.382 MHz;
FIG. 21 (b) is a diagram of one of the two sonic vortex wave generators of FIG. 21 (a) twisted 30 clockwise;
FIG. 22 is a phase diagram of FIG. 21;
FIG. 23 is a schematic diagram of a combined acoustic vortex wave of three acoustic vortex wave generators;
FIG. 24 is a schematic structural view of an acoustic subsurface.
Detailed Description
The embodiment of the application provides an acoustic super-surface and an acoustic vortex wave generator, which realize that a phased array which is annularly arranged around the propagation direction is generated after an incident sound wave enters the acoustic vortex wave generator, and the acoustic super-surface and acoustic vortex wave generator has a simple structure.
In order to make the objects, features and advantages of the present invention more comprehensible, the technical solutions in the embodiments of the present application will be clearly described in conjunction with the accompanying drawings in the embodiments of the present application, and it is apparent that the embodiments described in the following are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
With reference to the accompanying drawings, embodiments of the present application provide an acoustic super surface comprising:
is a cylindrical cavity structure;
the cylindrical cavity structure includes:
at least 4 phase units, each phase unit is a sector cylinder, and the at least 4 sector cylinders enclose a cylindrical cavity structure based on a central shaft of the cylindrical cavity structure;
at least 4 of the phase cells are arranged in a circular line over 0 to 2 pi in a phase gradient increasing manner.
Optionally, the two-dimensional side view of the phase element is an axisymmetric pattern, as shown in fig. 1;
the height h and the width l of each phase unit are consistent, and every two adjacent phase units are connected through a solid plate;
the shape of the side view two-dimensional pattern of each phase cell is generally in the shape of a bracket formed by left and right boundaries inside which is at least one rectangle corresponding to a diaphragm for generating a deflection phase.
Optionally, the number of the phase units is 6, and specifically includes: a first phase unit, a second phase unit, a third phase unit, a fourth phase unit, a fifth phase unit, and a sixth phase unit (refer to fig. 2 to 7);
all of the side view two-dimensional patterns (refer to fig. 2 (a) to 7 (a)) are axisymmetric patterns, both left-right and up-down. All phase cells are of equal height (h) and equal width (l).
As shown in fig. 8, the formula according to generalized Snell's lawθt is the incident angle, θi is the refraction angle, nt and ni are the refractive indices of the acoustic wave in two different substances, respectively, λ is the wavelength of the incident wave, +.>Is a phase gradient. Since the whole model is performed in air, n t ＝n i =1, so the formula can be reduced to:d is the path of the sound wave propagating in the cavity, and by changing the value of d, the transmitted sound wave can have any propagation direction. Further simplify and get->Where λ is a constant value, the wavelength formula c/f=λ, c is the velocity of the sound wave in air, f is the frequency of the incident sound wave, and all the results of the subsequent simulations of the present application are performed at f=0.5 MHz frequency. It is possible to change the value of d only to six phase units with deflection angles of 0 deg. -360 deg. and gradients of 60 deg., while at the same time ensuring high transmittance properties. All the following structural parameters meet the deflection angle and have the property of high transmittance, and the average transmittance reaches 98.3 percent. FIG. 24 is a model structure of an acoustic subsurface.
The deflection phase generated by the first phase unit is 0-5 degrees, the deflection phase generated by the second phase unit is 60-65 degrees, the deflection phase generated by the third phase unit is 120-126 degrees, the deflection phase generated by the fourth phase unit is 176-180 degrees, the deflection phase generated by the fifth phase unit is 233-240 degrees, and the deflection phase generated by the sixth phase unit is 297-300 degrees.
The optimum is, for example, that the deflection phase generated by the first phase unit is 0 °, the deflection phase generated by the second phase unit is 60 °, the deflection phase generated by the third phase unit is 120 °, the deflection phase generated by the fourth phase unit is 180 °, the deflection phase generated by the fifth phase unit is 240 ° and the deflection phase generated by the sixth phase unit is 300 °.
It has to be noted that the value here is a fixed value, since the phase cell size is already given, the deflection phase value is fixed. However, the conversion from the acoustic plane wave to the acoustic vortex wave can be realized by adjusting the width of the inlet and outlet of the phase unit and the length of the partition plate so as to achieve a deviation in the range of + -5 deg.. And the transmittance of each phase unit is more than 95%.
Thickness l of rectangle corresponding to all diaphragm plates of first phase unit and second phase unit 0 And width l 1 Are all corresponding and consistent;
width l of rectangle corresponding to all diaphragms of third, fourth, fifth and sixth phase units 1 Is the width l of the rectangle corresponding to the diaphragm plate of the first phase unit and the second phase unit 1 Half of (a) is provided.
The acoustic super surface is made of copper, and when the acoustic super surface is made of epoxy resin, the acoustic vortex wave can be converted into an acoustic plane wave.
The first phase unit, the second phase unit, the third phase unit, the fourth phase unit, the fifth phase unit, and the sixth phase unit will be described below:
fig. 2 (b) is formed by rotating the first phase unit of fig. 2 (a) by 50 ° to 57 ° clockwise based on the left boundary as the rotation axis, and the higher the degree, the higher the corresponding transmittance.
The lengths of the top and bottom edges of the left and right boundaries of the first phase unit are first w 1 ＝0.14λ～0.15λ；
The thickness of the top and bottom edges of the left and right boundaries of the first phase element is first h 1 ＝0.057λ～0.059λ；
Optimal examples are:
thickness of the boundary of the left and right boundaries of the first phase unit is a first w 2 ＝0.01λ～0.04λ。
The lengths of the top and bottom edges of the left and right boundaries of the first phase unit are first w 1 ＝0.14λ；
The thickness of the top and bottom edges of the left and right boundaries of the first phase element is first h 1 ＝0.057λ；
Thickness of the boundary of the left and right boundaries of the first phase unit is a first w 2 ＝0.04λ。
The first phase unit generates a deflection phase of 0 deg. while achieving high transmittance. By varying the parameter w 1 Resulting in a doorway width (l-2*w) 1 ) The transmittance can be made to reach 99.9% by changing, and l is the width of a unit cell and is a constant value.
The structural parameters of the specific first phase unit are shown in the following table 1, and the parameters of table 1 may be specifically shown in fig. 1, where the reference symbols in the present application are consistent, and the specific reference symbols in fig. 1 are referred to as:
| h | 0.6λ |
| l | 0.48λ |
| w 1 | 0.14λ |
| w 2 | 0.04λ |
| h 1 | 0.057λ |
| l 0 | 0.006λ |
| l 1 | 0.2λ |
TABLE 1
Fig. 3 (b) is formed by rotating the second phase unit in the clockwise direction by 50 ° to 57 ° based on the left boundary of the second phase unit in fig. 3 (a) as a rotation axis, and the higher the degree, the higher the corresponding transmittance.
The lengths of the top and bottom edges of the left and right boundaries of the second phase unit are second w 1 ＝0.19λ～0.21λ；
The thickness of the top and bottom edges of the left and right boundaries of the second phase unit is second h 1 ＝0.057λ～0.059λ；
Thickness of the boundary of the left boundary and the right boundary of the second phase unit is second w 2 ＝0.01λ～0.04λ。
Optimal examples are:
the lengths of the top and bottom edges of the left and right boundaries of the second phase unit are second w 1 ＝0.19λ；
The thickness of the top and bottom edges of the left and right boundaries of the second phase unit is second h 1 ＝0.057λ；
Thickness of the boundary of the left boundary and the right boundary of the second phase unit is second w 2 ＝0.04λ。
The second phase unit produces a deflection phase of 60 deg. while achieving high transmittance. By varying the parameter w only 1 Resulting in a doorway width (l-2*w) 1 ) The transmittance can be made to reach 99.6% by changing. W is compared with the first phase unit 1 Reduced by 0.05λ, i.eWidth of doorway (l-2*w) 1 ) The decrease by 0.1 lambda, the other parameters remain unchanged.
The structural parameters of the specific second phase unit are shown in the following table 2, and the parameters of table 2 may be specifically shown in fig. 1, and the reference symbols in this application are consistent, and the specific reference symbols in fig. 1 are referred to as follows:
TABLE 2
The aforementioned first phase unit and second phase unit are provided with only one partition.
Fig. 4 (b) is a view of the left boundary of the third phase unit in fig. 4 (a) as a rotation axis, rotated clockwise by 50 ° to 57 °, and the higher the degree, the higher the corresponding transmittance.
The lengths of the top and bottom edges of the left and right boundaries of the third phase unit are third w 1 ＝0.125λ～0.145λ；
The thickness of the top and bottom edges of the left and right boundaries of the third phase unit is third h 1 ＝0.108λ～0.115λ；
Thickness third w of the boundaries of the left and right boundaries of the third phase unit 2 ＝0.01λ～0.04λ；
Optimal examples are:
the lengths of the top and bottom edges of the left and right boundaries of the third phase unit are third w 1 ＝0.125λ；
The thickness of the top and bottom edges of the left and right boundaries of the third phase unit is third h 1 ＝0.108λ；
Thickness third w of the boundaries of the left and right boundaries of the third phase unit 2 ＝0.01λ；
The third phase unit comprises 2 transverse baffles;
the third phase unit generates deflection phase120 deg., while achieving high transmittance. By adding a diaphragm and varying the parameter w 1 Resulting in a doorway width (l-2*w) 1 ) The transmittance can be up to 90.7% by changing the thickness of the wall of the unit cell. Compared with the first phase unit and the second phase unit, the middle of the first phase unit and the second phase unit is provided with one more partition plate, the length of the partition plate is twice that of the first phase unit and the second phase unit, and the thickness l of the partition plate 0 (0.006 lambda) are equal. But the third phase unit has a thickness of 0.01λ which is one quarter of the thickness of the first phase unit and the second phase unit. The number of the partition plates is two, the width of the access opening is changed, the thickness of the wall of the third phase unit is reduced, and other parameters are kept unchanged.
The structural parameters of the specific third phase unit are shown in the following table 3, and the parameters of table 3 may be specifically shown in fig. 1, where the reference symbols in the present application are consistent, and the specific reference symbols in fig. 1 are referred to as:
| h | 0.6λ |
| l | 0.48λ |
| w 1 | 0.125λ |
| w 2 | 0.01λ |
| h 1 | 0.108λ |
| l 0 | 0.006λ |
| l 1 | 0.4λ |
TABLE 3 Table 3
Fig. 5 (b) is formed by rotating the fourth phase unit by 50 ° to 57 ° clockwise based on the left boundary of the fourth phase unit in fig. 5 (a) as a rotation axis, and the higher the degree, the higher the corresponding transmittance.
Length of top and bottom edges of left and right boundaries of the fourth phase element is fourth w 1 ＝0.15λ～0.175λ；
The thickness of the top and bottom edges of the left and right boundaries of the fourth phase element is fourth h 1 ＝0.108λ～0.11λ；
Thickness of the boundary of the left boundary and the right boundary of the fourth phase cell is fourth w 2 ＝0.01λ～0.04λ。
Optimal examples are:
length of top and bottom edges of left and right boundaries of the fourth phase element is fourth w 1 ＝0.15λ；
The thickness of the top and bottom edges of the left and right boundaries of the fourth phase element is fourth h 1 ＝0.108λ；
Thickness of the boundary of the left boundary and the right boundary of the fourth phase cell is fourth w 2 ＝0.01λ；
The fourth phase unit comprises 2 diaphragms.
The structural parameters of the specific fourth phase unit are shown in the following table 4, and the parameters of table 4 may be specifically shown in fig. 1, where the reference symbols in the present application are consistent, and the specific reference symbols in fig. 1 are referred to as:
| h | 0.6λ |
| l | 0.48λ |
| w 1 | 0.15λ |
| w 2 | 0.01λ |
| h 1 | 0.108λ |
| l 0 | 0.006λ |
| l 1 | 0.4λ |
TABLE 4 Table 4
Fig. 6 (b) is formed by rotating the fifth phase unit by 50 ° to 57 ° clockwise based on the left boundary of the fifth phase unit in fig. 6 (a) as a rotation axis, and the higher the degree, the higher the corresponding transmittance.
Lengths of top and bottom edges of left and right boundaries of the fifth phase unit fifth w 1 ＝0.175λ～0.185；
Thickness fifth h of top and bottom edges of left and right boundaries of the fifth phase unit 1 ＝0.108λ～0.11λ；
Thickness fifth w of the boundaries of the left and right boundaries of the fifth phase unit 2 ＝0.01λ～0.04λ。
Optimal examples are:
lengths of top and bottom edges of left and right boundaries of the fifth phase unit fifth w 1 ＝0.175λ；
Left and right boundaries of the fifth phase elementThickness of top and bottom edges fifth h 1 ＝0.108λ；
Thickness fifth w of the boundaries of the left and right boundaries of the fifth phase unit 2 ＝0.01λ；
The fifth phase unit comprises 2 diaphragms.
The structural parameters of the fifth phase unit are shown in the following table 5, and the parameters of table 5 may be specifically shown in fig. 1, where the reference symbols in the present application are consistent, and the specific reference symbols in fig. 1 are referred to as:
| h | 0.6λ |
| l | 0.48λ |
| w 1 | 0.175λ |
| w 2 | 0.01λ |
| h 1 | 0.108λ |
| l 0 | 0.006λ |
| l 1 | 0.4λ |
TABLE 5
The fourth phase unitAnd a fifth phase unit generating a deflection phase of 180 DEG, 240 DEG while achieving high transmittance. The transmittance of the fourth phase unit and the fifth phase unit was 99.9%,99.2%,99.9%, respectively. The fourth phase unit only changes the outlet width compared to the fifth phase unit, and the other parameters remain unchanged. The third phase element, the fourth phase element and the fifth phase element each have two intermediate partitions, simply by varying w 1 To change the entrance (l-2*w) 1 ) The size, the designed phase is obtained, and the effect of high transmittance is realized.
Fig. 7 (b) is formed by rotating 50 ° to 57 ° clockwise based on the left boundary of the sixth phase unit of fig. 7 (a) as a rotation axis, and the larger the degree, the higher the corresponding transmittance.
Lengths of top and bottom edges of left and right boundaries of the sixth phase element, sixth w 1 ＝0.18λ～0.20λ；
Thickness sixth h of top and bottom edges of left and right boundaries of sixth phase cell 1 ＝0.0285λ～0.029λ；
Thickness sixth w of the boundaries of the left and right boundaries of the sixth phase cell 2 ＝0.02λ～0.04λ。
Optimal examples are:
lengths of top and bottom edges of left and right boundaries of the sixth phase element, sixth w 1 ＝0.18λ；
Thickness sixth h of top and bottom edges of left and right boundaries of sixth phase cell 1 ＝0.0285λ；
Thickness sixth w of the boundaries of the left and right boundaries of the sixth phase cell 2 ＝0.02λ；
The sixth phase unit comprises 3 diaphragms.
Three clapboards are arranged in the middle of the sixth phase unit, the thicknesses of all clapboards are equal, the lengths of the clapboards are 0.2λ for the first phase unit and the second phase unit, and the lengths of the clapboards are 0.4λ for the third phase unit, the fourth phase unit, the fifth phase unit and the sixth phase unit. Sixth phase unit, first phase unit, second phase unit, third phase unit, fourth phase unitCompared with the fifth phase unit, the phase unit has a phase difference of (w 1 =0.18λ), thickness of lower plate (h 1 ) A reduction also occurs.
The structural parameters of the sixth phase unit are shown in the following table 6, and the parameters in table 6 can be specifically shown in fig. 1, and the reference symbols in the present application are consistent, and the specific reference symbols in fig. 1 are referred to as:
| h | 0.6λ |
| l | 0.48λ |
| w 1 | 0.18λ |
| w 2 | 0.01λ |
| h 1 | 0.0285λ |
| l 0 | 0.006λ |
| l 1 | 0.4λ |
TABLE 6
The embodiment of the application also discloses an acoustic vortex wave generator, 2 air columns and the acoustic super surface mentioned in the previous embodiment;
the sound wave incident end and the sound wave emergent end of the acoustic super surface are respectively connected with an air column.
Simulation of the acoustic vortex wave generator of the embodiment of the present application will be described in detail below:
as shown in fig. 9, an air column is arranged at the acoustic ultrasonic wave incident end and the acoustic wave emergent end, which is formed by encircling 6 phase units on the acoustic ultrasonic surface of the acoustic vortex wave generator. The plane sound wave without vortex effect enters the structural body and generates vortex sound wave after exiting. The frequency f=0.5 MHz of the sound wave enters from an annular air column, and is emitted from an annular air column, and the whole simulation experiment is carried out in air.
As shown in fig. 10, the phase diagrams of the first phase unit, the second phase unit, the third phase unit, the fourth phase unit, the fifth phase unit and the sixth phase unit respectively show that the deflected phases are 5 °,60 °,126 °,176 °,233 °,297 °, the horizontal axis represents the phase angles of the first phase unit, the second phase unit, the third phase unit, the fourth phase unit, the fifth phase unit and the sixth phase unit in sequence, and the vertical axis represents the phase angles of the corresponding deflection.
As is clear from the sound pressure surface view of fig. 11 (a), which is an outgoing air chamber, a vortex sound wave is generated, which is a normalized image, fig. 11 (b) which is a sectional view of an outgoing air column, which is a phase diagram of the vortex sound wave, and fig. 11 (c) which is an absolute sound pressure diagram of a sectional view, it is clear from fig. 11 (c) that there is a sound pressure singular point in between. Is also an important feature of vortex waves, and the most middle sound pressure value is the lowest.
As shown in fig. 12, the sectional views of the emergent air column from the near to the far are respectively the phase diagrams of 0.1λ,0.2λ,0.5λ,0.75λ and 1λ, and as the distance is far, the phase is deflected in the clockwise direction.
As shown in fig. 13, when the incident frequency is changed, the transmittance of the plane wave is converted into a vortex wave, and the horizontal axis represents the frequency of the incident sound wave and the vertical axis represents the transmittance at different frequencies of the incident sound wave. It can be seen from the figure that at some frequencies the transmittance can reach 100%.
Characteristics of the acoustic vortex wave generator of fig. 9: (1) The frequency broadening effect, i.e. the generation of acoustic vortex waves in a certain range close to the center frequency, is achieved. The center frequency is a certain incident frequency at which lambda is fixed and the size of the supersurface is fixed. When the frequency of the incident wave changes (this frequency is near the center frequency), an acoustic vortex wave can also be realized. (2) Has high transmissivity effect, and can transmit very high transmissivity even full transmissivity at certain incident sound wave frequency. Transmittance = outgoing sound wave power/incoming sound wave power. (3) The structure is simple, only 6 simple phase units with the phase gradient of 60 degrees are provided, and the phase units are simpler than other sound vortex wave generators capable of generating sound vortex waves, and are easier to manufacture and produce.
As shown in fig. 14, the wavelength formula c/f=λ is that when the size of the structure is fixed at f=0.5 MHz, the frequency of the incident sound wave is changed, and thus a sound vortex wave whose topology number is the number of sound wave rotation changes in the unit wavelength can be generated. The four simulated structures of fig. 14 all have the same length of the entrance cavity of 3λ and the exit cavity of 9λ.
As shown in fig. 15, the fixed structure size f=0.5 MHz, and the acoustic super surface fills are air and CO, respectively 2 At different incident acoustic wave frequencies. The solid line is filled with air, and the dotted line is filled with CO 2 . The horizontal axis represents different incident sound wave frequencies and the vertical axis represents transmittance. As can be seen from the graph, the transmittance is different under different incidence frequencies, and the transmittance can reach more than 90% in certain ranges.
The phase property is the most fundamental feature of swirl. Vortex is formed when the sound wave has a phase that varies uniformly along the circumferential angle. The phase ψ (r, θ, z) =lθ, where (r, θ, z) is a cartesian coordinate, z is the center path of the vortex, and l is a signed integer, called the topological charge number (i.e. the value of m in this patent), which represents the number of times the acoustic wave twists in one wavelength, the larger the topological charge number, the faster the beam rotates along the central axis, the larger the angular momentum, the larger the moment generated, and its sign determines the direction of the spiral. The swirling acoustic wave has angular momentum and the resulting moment can manipulate the movement of the particles. (the cells in the animal blood vessel can be controlled in a non-invasive way, and the understanding is convenient under the simple introduction)
Fig. 14 shows that different incident sound waves are incident at different frequencies and different wavelengths. The different deflection phases of the ultrasonic wave with different wavelengths are different on the super surface, so that the phases which are uniformly changed along the circumferential angle are different, and the meaning of the ultrasonic vortex wave shown in fig. 14 is that the ultrasonic vortex wave with controllable topological charge number is realized.
In FIG. 15, when the super surface is filled with air and CO2, the refractive indexes of the air and CO2 to the sound wave are different, and the arrangement on the loop line of 0-2 pi can be realized in coordination with the change of the frequency range. The frequency range over which an acoustic plane wave can be converted into an acoustic vortex wave will be different.
As shown in fig. 16 and 17, fig. 16 (a) shows the phase of the sound vortex wave generated by the sound vortex wave generator at the incident sound wave of f=0.5 MHz, as shown in fig. 16 (b). When the acoustic super-surface is twisted clockwise by 30 ° as shown in fig. 17 (a), it is found that the phase is deflected counterclockwise by 30 ° as shown in fig. 17 (b). Fig. 16 (b) and 17 (b) are cross-sectional views at the same position at a position z=0.25 cm from the acoustic super surface of the acoustic vortex wave generator, and the occurrence of deflection in the counterclockwise direction is apparent from the phase of fig. 17 (b). Fig. 18 shows the angle of clockwise rotation of the acoustic super-surface of the acoustic vortex wave generator and the phase counter-clockwise rotation. The horizontal axis is the angle of clockwise torsion of the acoustic super surface of the acoustic vortex wave generator, and the vertical axis is the angle of counterclockwise phase deflection.
The phase of the acoustic vortex wave is regulated by regulating the temperature of the filler of the acoustic super surface.
As shown in fig. 19, (a) the filler is air, and the phase is deflected counterclockwise by different angles at different temperatures. (b) For z=2.5λ, f=0.384 MHz at the same position, the structural parameters of the structures were all designed according to the wavelength λ of table 1.
As shown in fig. 20, based on the phase deflection of the filler air at different temperatures in fig. 19, the horizontal axis represents different temperatures of the filler air, and the vertical axis represents different deflection phase angles.
The phase of the acoustic vortex wave can be understood by regulating the temperature of the filler of the acoustic super surface: (1) The topology can only be changed before by changing the frequency, where the temperature of the filling can be changed to change the topology of the acoustic vortex wave. (2) By changing the temperature, the phase of the acoustic vortex wave is changed.
As shown in fig. 21 (a) and 21 (b), the filler in the acoustic super surface is air, the acoustic super surface on the right and the acoustic super surface on the left are identical, the incident frequency is 0.382MHz, and the size is fixed. It can be seen from fig. 21 (a) that two sound vortex waves having opposite rotation directions are generated, that is, the rotation directions of the sound vortex waves are controlled by means of a combination of two sound super surfaces. Fig. 21 (b) is a phase diagram at z=0.5 cm from the left Bian Shengxue supersurface, and by twisting the right acoustic supersurface in fig. 21 (a) clockwise by 30 °, the opposite direction of rotation of the acoustic vortex wave is also generated, and the phase of the right acoustic vortex wave is deflected clockwise by 60 °.
The characteristics are as follows: (1) The acoustic vortex wave is controlled by a combination of two acoustic super surfaces. And (2) the regulation and control of the rotation direction of the sound vortex wave can be realized. (3) And accurately calculating the relation between the rotating phase angle and the torsional acoustic super surface.
FIG. 18 above shows that when a single supersurface rotates, the acoustic vortex wave is also rotated by the same angle as the supersurface rotates by a certain angle. However, in fig. 22, when the scroll wave is twisted by a certain angle, the angle of the wave is twice as large as that of the certain angle. FIG. 18 shows the revolution of the subsurface and the revolution of the sonic vortex. The right hand super surface of fig. 22 rotates once and the acoustic vortex wave rotates two weeks. Thus, the speed of phase regulation can be improved by combining two sound super surfaces. When the sound vortex wave is transferred to a certain sound absorbing object, the sound vortex wave transfers torsion momentum to the sound absorbing object, and the sound absorbing object rotates. The angle of torsion is different and the torsional speed of the sound absorbing object is also different.
Fig. 18 is a clockwise rotation, fig. 22 is a rotation of clockwise rotation to counterclockwise rotation, a direction of torsion is changed, and a direction of phase change is changed. For sound absorbing objects the direction of rotation will change.
As shown in fig. 23, the re-decoding of the acoustic vortex wave into an acoustic plane wave is achieved by means of a combination of three acoustic super surfaces.
According to the sound vortex wave generator, through the acoustic super surface of the cylindrical cavity structure, the phase units of the at least 4 fan-shaped cylinder structures are surrounded based on the central axis of the cylindrical cavity structure, meanwhile, the at least 4 phase units are annularly arranged on 0 to 2 pi in a phase gradient increasing mode, so that a phased array which is annularly arranged around the propagation direction is generated after incident sound waves enter the sound vortex wave generator, and the sound vortex wave generator is simple in structure.
The above embodiments are merely for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (11)
1. An acoustic super surface is characterized by being of a cylindrical cavity structure;
the cylindrical cavity structure includes:
at least 4 phase units, each phase unit is a sector cylinder, and the at least 4 sector cylinders enclose a cylindrical cavity structure based on a central shaft of the cylindrical cavity structure;
at least 4 phase units are arranged in a loop line on 0 to 2 pi in a phase gradient increasing manner;
the side view two-dimensional graph of the phase unit is an axisymmetric graph;
the height h and the width l of each phase unit are consistent, and every two adjacent phase units are connected through a solid plate;
the shape of the side view two-dimensional graph of each phase unit is a bracket shape formed by a left boundary and a right boundary, and the inside of the left boundary and the right boundary is at least one rectangle corresponding to a diaphragm plate for generating deflection phase.
2. The acoustic super-surface of claim 1, wherein the number of phase units is 6, comprising: a first phase unit, a second phase unit, a third phase unit, a fourth phase unit, a fifth phase unit, and a sixth phase unit; the deflection phase generated by the first phase unit is 0-5 degrees, the deflection phase generated by the second phase unit is 60-65 degrees, the deflection phase generated by the third phase unit is 120-126 degrees, the deflection phase generated by the fourth phase unit is 176-180 degrees, the deflection phase generated by the fifth phase unit is 233-240 degrees, and the deflection phase generated by the sixth phase unit is 297-300 degrees.
3. The acoustic subsurface according to claim 1, wherein the wavelength of the incident wave incident into the acoustic subsurface is λ.
4. An acoustic super surface according to claim 3, wherein the thickness l of the rectangle corresponding to all diaphragms of the first and second phase units 0 And width l 1 Are all corresponding and consistent;
width l of rectangle corresponding to all diaphragms of third, fourth, fifth and sixth phase units 1 Is the width l of the rectangle corresponding to the diaphragm plate of the first phase unit and the second phase unit 1 Half of (a) is provided.
5. An acoustic super surface according to claim 3, wherein,
the lengths of the top and bottom edges of the left and right boundaries of the first phase unit are both the first w 1 ＝0.14λ～0.15λ；
The thicknesses of the top edge and the bottom edge of the left boundary and the right boundary of the first phase unit are respectively the first h 1 ＝0.057λ～0.059λ；
Thickness of the boundary of the left and right boundaries of the first phase unit is a first w 2 ＝0.01λ～0.04λ。
6. An acoustic super surface according to claim 3, wherein,
the top and bottom edges of the left and right boundaries of the second phase unit are each of the length of the second w 1 ＝0.19λ～0.21λ；
The top and bottom edges of the left and right boundaries of the second phase unit are both of a thickness of a second h 1 ＝0.057λ～0.059λ；
Thickness of the boundary of the left boundary and the right boundary of the second phase unit is second w 2 ＝0.01λ～0.04λ。
7. An acoustic super surface according to claim 3, wherein,
the top and bottom edges of the left and right boundaries of the third phase unit are each of a third w 1 ＝0.125λ～0.145λ；
The thicknesses of the top edge and the bottom edge of the left boundary and the right boundary of the third phase unit are all the third h 1 ＝0.108λ～0.115λ；
Thickness third w of the boundaries of the left and right boundaries of the third phase unit 2 ＝0.01λ～0.04λ；
The third phase unit comprises 2 diaphragms.
8. An acoustic super surface according to claim 3, wherein,
the top and bottom edges of the left and right boundaries of the fourth phase element are each of length of a fourth w 1 ＝0.15λ～0.175λ；
The thicknesses of the top edge and the bottom edge of the left boundary and the right boundary of the fourth phase unit are both the fourth h 1 ＝0.108λ～0.11λ；
Thickness of the boundary of the left boundary and the right boundary of the fourth phase cell is fourth w 2 ＝0.01λ～0.04λ；
The fourth phase unit comprises 2 diaphragms.
9. An acoustic super surface according to claim 3, wherein,
the lengths of the top and bottom edges of the left and right boundaries of the fifth phase element are both the fifth w 1 ＝0.175λ～0.185；
The thicknesses of the top edge and the bottom edge of the left boundary and the right boundary of the fifth phase unit are respectively the fifth h 1 ＝0.108λ～0.11λ；
Thickness fifth w of the boundaries of the left and right boundaries of the fifth phase unit 2 ＝0.01λ～0.04λ；
The fifth phase unit comprises 2 diaphragms.
10. An acoustic super surface according to claim 3, wherein,
the top and bottom edges of the left and right boundaries of the sixth phase element are each of length six w 1 ＝0.18λ～0.20λ；
The thicknesses of the top edge and the bottom edge of the left boundary and the right boundary of the sixth phase unit are all the sixth h 1 ＝0.0285λ～0.029λ；
Thickness sixth w of the boundaries of the left and right boundaries of the sixth phase cell 2 ＝0.02λ～0.04λ；
The sixth phase unit comprises 3 diaphragms.
11. An acoustic vortex wave generator comprising:
2 columns of air, an acoustic subsurface according to any one of claims 1 to 10;
the sound wave incident end and the sound wave emergent end of the acoustic super surface are respectively connected with an air column.
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