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Reflection type underwater sound metasurface design method for realizing underwater sound regulation and control

A design method and metasurface technology, applied in design optimization/simulation, special data processing applications, geometric CAD, etc., can solve the problem of inflexible control, lack of independent design methods for underwater acoustic metasurfaces, and disturbance of underwater metasurface unit acoustics Control parameters and other issues to achieve the effect of flexible control methods, strong replaceability, and reduced coupling

Active Publication Date: 2021-12-24
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that it is currently mainly used for periodic underwater sound field regulation, and it is relatively challenging to realize non-periodic underwater sound fields, such as focusing
Moreover, regulation is usually not flexible enough due to the need for the coordinated design of a set of metasurface units
[0005] In addition, in the underwater acoustic environment, the fluid-solid coupling between water and solids will cause the vibration of the solid structure of the underwater acoustic metasurface, resulting in mutual coupling of the vibrations of the underwater acoustic metasurface units, disturbing the original independent design of the underwater metasurface unit. Acoustic control parameters bring great challenges to the independent design of hydroacoustic metasurfaces
Therefore, it is very necessary to realize the fine regulation of various complex underwater acoustic fields by independently designing reflective underwater acoustic metasurfaces, and the independent design methods for underwater acoustic metasurfaces proposed so far are quite scarce.

Method used

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  • Reflection type underwater sound metasurface design method for realizing underwater sound regulation and control
  • Reflection type underwater sound metasurface design method for realizing underwater sound regulation and control
  • Reflection type underwater sound metasurface design method for realizing underwater sound regulation and control

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Embodiment 1

[0053] In this embodiment 1, the abnormal sound beam deflection under the incident plane wave sound field is realized, wherein the acoustic surface impedance boundary can be calculated by the formula in step (2) as

[0054]

[0055] where Φ(x)=kxsinθ i -kx(coshβsinθ r +i sinhβsinθ r ), θ i and θ r Indicates the angle of incidence and angle of reflection, respectively, and β indicates the attenuation factor of the reflection amplitude of the reflected wave in the direction perpendicular to the propagation direction, and the value range is β≥0, where β=0 means no attenuation; A r Indicates the amplitude ratio of the reflected wave to the incident wave. In order to ensure independent design feasibility, A r The value of should ensure that Z s (x, 0)≥0 holds true for all x.

[0056] Take θ in this embodiment 1 i = 0°, θ r =70°, β=0.1, A r =0.995, a=λ / 20, b=λ / 10, d=λ / 50, where λ=2π / k=0.3m is the underwater acoustic wavelength when the frequency is 5000 Hz.

[0057] i...

Embodiment 2

[0061] In this embodiment 2, the single-point acoustic focusing under the incident plane wave sound field is realized, and its acoustic surface impedance boundary can be calculated by the formula in step (2) as

[0062]

[0063] where Φ(x)=kxsinθ i ;A r and θ i Same as above definition; (x f ,z f ) indicates the position of the focus, and represent the first kind of 0-order and 1-order Hank functions, respectively; Indicates the distance from each point on the hypersurface to the focal point.

[0064] Take θ in this embodiment 2 i = 0°, (x f ,z f ) = (3λ, 0.5λ), A r =2.2, a=λ / 20, b=λ / 10, d=λ / 50, where λ=2π / k=0.3m is the underwater acoustic wavelength when the frequency is 5000Hz.

[0065] Figure 6 Acoustic surface impedance distribution provided by theoretically required and optimally designed metasurface units for realizing single-point acoustic focusing of underwater reflected acoustic waves in the embodiment of the present invention. It can be seen that ...

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Abstract

The invention belongs to the technical field of underwater sound, and particularly relates to a reflection type underwater sound metasurface design method for realizing underwater sound regulation and control. On the basis of acoustic surface impedance boundary conditions, an underwater acoustic metasurface unit for realizing theoretical acoustic surface impedance is designed by adopting a topological optimization mode, and the limitation of vibration coupling of the underwater acoustic metasurface unit is introduced into a topological optimization framework, so that the coupling of solid vibration of the metasurface is very effectively reduced, and the effectiveness of underwater acoustic metasurface design is ensured; therefore, the regulation and control of the underwater reflection sound field are realized. According to the design mode provided by the invention, artificial participation is not needed, customization as required can be realized, the replaceability of the underwater acoustic metasurface unit is high, the designed underwater acoustic metasurface regulation and control mode is flexible, a new scheme is provided for the design of the underwater acoustic metasurface, the practical application of the underwater acoustic metasurface in various fine and complex underwater sound field control can be promoted; the invention has important application value in the engineering fields of seabed resource exploration, acoustic particle manipulation, medical holographic imaging and the like.

Description

technical field [0001] The invention belongs to the technical field of underwater acoustics, and in particular relates to a reverse independent design method for a reflective underwater acoustic metasurface that realizes accurate control of underwater acoustics. Background technique [0002] For reflective hydroacoustic metasurfaces, the current design methods are mainly divided into two types: [0003] The first: an independent design based on the generalized Snell theorem. By independently designing each metasurface unit and assembling metasurface units with different reflection phases together, the regulation of underwater acoustic waves can be realized according to the phase gradient on the underwater acoustic metasurface. The disadvantage is that it cannot show perfect control performance for some extremely complex sound fields, such as abnormal reflections with large deflection angles. [0004] The second type: collaborative design based on grid diffraction theory. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F30/17G06F30/20
CPCG06F30/17G06F30/20
Inventor 周红涛汪越胜王艳锋
Owner TIANJIN UNIV
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