Ring-cone resonator cell for generating stable standing vortex fields as a standing wave

Abstract

Resonator cell based on the principle of a Helmholtz resonator, consisting of 1.1 a resonance cavity and 1.2 an opening for coupling to a surrounding medium (13), characterized in that 1.3 the annular resonance cavity (1) is essentially toroidal and has a centrally arranged cone element (2), 1.4 wherein an axially extending gap (4) is formed between the resonance cavity (1) and the central cone element (2), which causes a non-linear coupling between pressure and suction fields, 1.5 wherein the standing wave (12) generated in the resonance cavity (1) is not reflected in the cavity, but propagates stably into the surrounding medium (13) via the gap coupling, 1.6 wherein periodic pressure changes in the gap area result in a continuous energy transfer into the medium (13), so that a free, self-stabilizing vortex and vibration field with a defined axial end is formed (17), 1.7 which enables directed coupling without an external reflector.

Description

Technical field

[0001] The invention relates to the field of acoustic and fluid dynamic resonance systems, in particular geometries for generating toroidal vibration and vortex fields in which standing waves persist in the medium in a self-stabilizing manner. State of the art

[0002] Acoustic resonators and transducers are used to generate, focus, or dampen sound or pressure waves. A key factor is the formation of so-called standing waves, which generally arise from the superposition of incoming and reflected waves of the same frequency. This results in stationary pressure maxima (antinodes) and minima (nodes). Such waves typically occur in closed or semi-open cavities whose resonant frequency is determined by the geometry and the medium; their formation usually occurs via reflection at boundary surfaces.

[0003] Currently, standing waves are realized in various resonance and transducer systems that differ in their design, frequency range, and application. The known state of the art can be categorized according to the underlying resonance principles and coupling mechanisms. The main known groups include: 1. Resonator and absorber systems 2. Transducer-based resonance systems 3. Geometrically shaped field structures 4. Application-oriented systems without internal field coupling 4.1 Damping and Acoustic Black Hole (ABH) Structures 4.2 Sonar and radar systems 4.3 Massage device

[0004] These groups are characterized below in point form based on selected sources and intellectual property rights.

[0005] Resonator and absorber systems include devices that store or dissipate acoustic energy in cavities or structured surfaces to influence sound levels, frequency distribution, or resonance behavior.

[0006] Helmholtz resonators classically consist of a volume (cavity) with one or more openings / necks through which an oscillating fluid flow is coupled to the surrounding medium. The resulting resonant frequency is determined by the cavity volume and neck geometry (for many: US 6782109 B2, more in the appendix).

[0007] Microperforated panels (MPP) based on the Maa theory (DY Maa) extend this principle to surface absorbers with numerous small flow channels, where friction and inertial effects within the perforated channel determine the absorption. In such microperforated designs, numerous individual cavities form a distributed resonance structure, enabling effective attenuation of a broader frequency range. These systems store sound energy as internal pressure fluctuations and release them to the surrounding medium with a phase shift through the opening(s) or pores; they primarily serve for damping and linear resonance control.

[0008] A corresponding resonator and absorber system is disclosed in CN 110560348 B. This patent describes a MEMS ultrasonic transducer array comprising a multitude of microstructured Helmholtz cavities formed as a perforated array in a silicon wafer and coupled to a piezoelectric membrane. Each cavity forms a closed resonant cavity with a microperforated opening through which acoustic energy is exchanged with a phase shift between the chamber and the medium. The simultaneous excitation of several such cavities results in a uniform pressure distribution and increased sound pressure within the transducer's operating range. The resonant frequency is determined by the ratio of cavity volume, opening area, and channel length. Helmholtz resonators of this type operate in the linear acoustic range and are typically used for sound attenuation or to increase the acoustic efficiency of MEMS transducers.

[0009] In Helmholtz resonators, the standing wave is largely confined within the resonant cavity. Coupling into the free medium leads to rapid energy dissipation because the necessary reflection point is lacking. Thus, a permanently stable, free-terminating sound field is not generated. For applications where the resonant field is intended to interact with the surrounding medium, for example, for structuring liquids, plasmas, or other fluidic media, such resonators would have to be directly immersed in the medium, which is structurally complex and results in significant losses.

[0010] Helmholtz and microperforation resonators (MPPs) store acoustic energy within a sealed cavity. The resulting standing wave remains confined to the cavity and rapidly attenuates upon exiting into the surrounding medium due to the absence of back reflection. Therefore, such systems are primarily suitable for passively influencing sound levels or frequency spectra within enclosed spaces, but not for generating free, directional, or self-stabilizing sound fields.

[0011] Another well-known device for generating standing waves is the piezoelectric and microelectromechanical transducer (MEMS), in which mechanical vibrations are electrically excited and coupled into the surrounding medium. These transducers utilize thin membranes positioned between a support plate and a back wall, generating pressure waves through periodic movement. A standing wave forms within the space between the membranes, its resonant position determined by the cavity depth and membrane stiffness. This resonance is based on the reflection of the emitted wave at the back wall, thereby stabilizing the field distribution within the cavity.

[0012] Piezoelectric and microelectromechanical transducers generate standing waves through the vibration of thin membranes between solid interfaces. These systems typically rely on a reflective back wall to maintain the standing wave. The resulting field therefore remains stable within the structure, while it rapidly loses coherence upon transitioning to the open medium. Controlled coupling or propagation of the standing wave outside the structure is not possible with these designs, thus limiting their suitability for open media.

[0013] European patent EP 3 799 966 B1 discloses a piezoelectric transducer in which a thin diaphragm is arranged between a support plate and a rear-mounted resonance chamber. The acoustic efficiency is optimized by the λ / 2 resonance condition of the chamber length with respect to the operating frequency. The rear wall serves as a reflective surface, at which the emitted wave is partially reflected and superimposed again with the diaphragm. In this way, a standing wave is created within the cavity, which amplifies the sound pressure at the diaphragm front.

[0014] The system described in EP 3 799 966 B1 operates in the linear acoustic range and relies on the resonance between the diaphragm and the rear wall to achieve increased efficiency. When the wave is emitted into the free medium, it rapidly loses its coherence due to the lack of feedback. Self-stabilizing or toroidal field formation is not provided for in this design, nor is nonlinear coupling between pressure and vacuum zones. Such systems therefore primarily serve for signal and energy transmission within the transducer, but not for the formation of stable, free-floating wave fields or vortex structures.

[0015] The technical problem with known piezoelectric and microelectromechanical transducers lies in the fact that they can only maintain a standing wave within the transducer itself. A stable propagation of the wave into the surrounding medium is not possible, as the energy dissipates uncontrollably without reflective boundaries. Thus, a structure capable of selectively and self-stabilizing the resonant energy into free space, in order to form a coherent, directed field structure there, is lacking.

[0016] Another well-known group of systems for influencing acoustic energy comprises structural damping elements, in which the component's geometry is specifically designed to reduce or absorb vibrational energy. Acoustic black hole (ABH) structures and conical recesses in panels serve to locally concentrate vibrational energy and convert it into heat through dissipation. They rely on a geometric thickness gradient that reduces the local phase velocity of sound towards the edge, thereby creating an energy gradient. Such systems are used for vibration damping and absorption and are applied in lightweight construction, aerospace, and acoustic components. Their purpose is to reduce vibrations, not to amplify or control a sound field.

[0017] ABH systems and geometrically tapered structures are designed for the local concentration and damping of vibrational energy. They convert the coupled energy into heat through dissipation, thereby deliberately preventing feedback or resonance amplification. Such structures therefore do not form standing or stable waves. They are primarily designed for energy absorption and do not enable either directed field formation or reproducible wave propagation in the medium. Examples of this are provided by DE 10 2015 100 442 A1 (Active Acoustic Black Hole System for Vibration Reduction), US 10 900 934 B2 (Acoustic Black Hole for Sensing Applications), and US 11 946 523 B2 (Broadband Effective Vibration Absorber Using the Acoustic Black Hole Phenomenon), as well as the scientific publication by Li Ma; Li Cheng

[2023] , “Vibration and sound radiation of an acoustic black hole plate immersed in heavy fluid,” in: The Journal of the Acoustical Society of America, J. Acoust. Soc. On.154, pp. 179-190, such damping and absorber solutions. These systems are based on geometrically determined energy absorption and do not exhibit active feedback or conservation of vibrational energy. A self-stabilizing wave or a wave that can be freely maintained in the medium is not disclosed in these systems.

[0018] Another well-known class of systems for generating and controlling acoustic fields comprises focusing or vortex-generating ultrasonic transducers, in which the field distribution is determined by the targeted geometric or phase-modulated shaping of the transducer surface. Concave, conical, or spiral transducer surfaces allow for the generation of ring-shaped or point-shaped focus zones as well as rotationally symmetrical sound fields.

[0019] US patent 7,273,459 B2 describes a so-called vortex transducer in which a specially shaped concave or ring-shaped concentric transducer surface generates a ring-shaped focal zone with a central pressure minimum. The vortex formation results from the targeted phase front shaping of the emitted wave. The system generates focused ultrasound fields that are used, among other things, in medical and industrial applications (especially material processing).

[0020] Vortex and focus transducers generate ring-shaped or spiral field structures that resemble a vortex, either optically or acoustically. However, the field shape is primarily determined by the geometry of the transducer surface. There is no internal feedback between pressure and suction zones, so the field is not self-stabilizing. Outside the focal point, the generated vortex field rapidly loses its structure and cannot sustain itself. Therefore, such systems are not suitable for generating permanently stable, free vortex or standing wave fields.

[0021] The following are further examples of application-oriented systems without internal field coupling, in order to examine the respective standing wave principles applied.

[0022] One group of known systems uses acoustic or mechanical vibrations in the form of standing waves to transfer energy specifically to biological tissues and surfaces. Such systems are used particularly in the medical and biomechanical fields.

[0023] Utility model DE 20 2025 001 316 U1 describes, by way of example, a device in which standing or polarized waves are used for tissue or massage stimulation. Several vibration sources are combined to generate a defined pressure distribution within a contact area. These devices are based on the superposition of mechanical vibrations and use a fixed support or reflective surface to stabilize the field.

[0024] The medical vibration or massage device under consideration here generates standing or polarized waves within fixed contact surfaces. These waves are based on the superposition of multiple vibration sources and reflection at the skin or tissue surface. As a result, the generated field remains locally confined and dissipates rapidly outside the contact zone. A stable field structure in the free medium is not achievable with these designs; energy transfer remains essentially limited to the directly adjacent tissue.

[0025] Another well-known application of standing waves is found in radar and sonar systems, where acoustic or electromagnetic waves are used to measure distances, velocities, or material boundaries. Distance measurement systems, such as those disclosed in DE 10 2016 004 906 A1, utilize standing electromagnetic or acoustic waves for resonance or time-of-flight measurement. The generated wavefronts serve as a reference signal for determining distances or material transitions.

[0026] Radar and sonar systems primarily use standing waves as a measurement or reference signal for determining distance and travel time. The generated wavefronts are selectively reflected to create an interference pattern for signal processing. These systems do not form independent, stable wave fields within the medium, but serve solely for measurement and evaluation purposes. Nonlinear self-coupling between pressure and suction zones is not apparent. Description of the invention

[0027] Problem. The known state of the art describes a variety of resonators, transducers, and field structures that predominantly operate in the linear or damping regime. All systems share the common feature that standing waves are regularly generated and stabilized by reflection at fixed boundaries. However, no system disclosed or suggested in the known state of the art maintains a standing wave in a free medium or utilizes nonlinear coupling between pressure and suction zones to form a stable, toroidal vortex field.

[0028] In summary, it can therefore be stated that the known resonance, transducer, and damping systems are based on linear or reflective principles. They require fixed boundaries to generate standing waves and lack internal feedback between pressure and suction zones. A system that stabilizes a standing wave in a free medium through nonlinear self-coupling and simultaneously allows for a directed alignment of the field is not disclosed in the prior art.

[0029] Known resonance systems require fixed boundaries to generate surrounding waves and remain unstable without these boundaries. Furthermore, no geometry is known that allows self-coupling between pressure and suction zones in a free medium.

[0030] The technical challenge, therefore, lies in providing a resonator system capable of maintaining a standing wave not only within a cavity but also stably in the free medium, without relying on external boundary surfaces or reflectors. Furthermore, the generated field should exhibit a directed orientation and a defined, reproducible terminal maximum, enabling it to interact selectively with surrounding media.

[0031] Problem and solution. Claim 1 of US 6,792,907 B1 discloses a variably tunable resonator comprising a housing with a chamber and a neck section that provides a fluid connection between the chamber and a channel. Furthermore, a motor speed sensor and a control device are provided which, depending on the detected rotational speed, adjust at least one of the parameters—chamber volume, neck length, or neck diameter—to tune the damping to a desired sound frequency. Additionally, the system includes a noise sensor and a vibratory actuator located in the chamber that responds to the detected noise parameters to compensate for an unwanted sound frequency in the channel by means of vibration.The patent addresses the technical problem that, in classical Helmholtz resonators, while the standing wave is generated within the cavity, stable coupling outside the resonance chamber is not possible because the field dissipates into the surrounding medium without reflection limitations. This problem, particularly the limited effective zone of conventional Helmholtz resonators, is addressed by the solution according to the invention.

[0032] In summary, the principle consists of a resonance cavity and an opening for coupling to a surrounding medium (general term).

[0033] Claim 1 of the invention provides the individual features in which the annular resonance cavity 1 is essentially toroidal and has a centrally arranged cone element 2, wherein an axially extending gap 4 is formed between the resonance cavity 1 and the central cone element 2, which causes a nonlinear coupling between pressure and suction fields, wherein the standing wave 12 generated in the resonance cavity 1 is not reflected in the cavity, but propagates stably into the surrounding medium 13 via the gap coupling, wherein a continuous energy transfer into the medium takes place through periodic pressure changes in the gap region, so that a free, self-stabilizing vortex and vibration field with a defined axial end is formed, thereby enabling a directed coupling without an external reflector, hereinafter referred to as the coupled standing wave 17.This eliminates the fundamental limitation of the Helmholtz principle; that is, the standing wave 12 is no longer confined to the interior but can persist outside the resonator as a coherent, self-stabilizing vortex and vibration structure, as described above. This combination of features enables continuous energy transfer into the surrounding medium 13 and leads to the formation of a free, directed, and reproducible sound field that requires no external reflectors and allows for the targeted use of resonance energy in open space. The term "essentially toroidal" with regard to the shape of the annular resonance cavity 1 is to be understood as meaning that deviations from an ideal torus shape are permissible as long as the annular, circumferential character of the resonance cavity is maintained.

[0034] Further advantageous embodiments result from dependent claims 2 to 9 and from the use according to claim 10, to which reference is made below.

[0035] According to claim 2, the height and intensity of the standing wave 12 formed in the center of the resonator cell can be selectively controlled via the excitation amplitude and the density of the medium 13. This allows the energy density of the field structure to be adapted to different operating conditions, enabling precise control of the resonance effect and the output coupling behavior.

[0036] Claim 3 extends the invention to different media and excitation methods. The resonance system can be operated with gases, liquids, plasmas, or elastically coupled solids and can be excited acoustically, mechanically, electrically, magnetically, or piezoelectrically. This versatility allows the device to be used in a wide variety of technical and physical environments.

[0037] According to claim 4, the resonance can also be passively induced by a flowing medium, resulting in a self-exciting field formation. This enables energy-autonomous operation of the device, in which the system is set into resonance by the movement of the medium itself and generates a stable boundary wave with a defined boundary layer formation.

[0038] The configuration according to claims 5 and 6 enables a matrix arrangement of several cells, thereby allowing directed field condensations and focusing to be formed. This combination of features means that the standing wave 12 generated in the device no longer needs to be reflected within a cavity, but instead propagates stably into the medium 13 and forms a free-terminating, reproducible field structure there.

[0039] Dependent claims 7 to 9 define advantageous further developments, such as a scalable frequency design, the gradient variation of geometric parameters and the modifiable tip of the cone element 3, in order to adapt the field pattern, exit angle and stability of the coupled standing wave 17 to different media.

[0040] Claim 10 relates to the use of the resonator cell or matrix for the formation and stabilization of standing toroidal fields in gases, liquids, solids, or plasmas. Between the annular resonance cavity 1 and the cone 2, a standing wave 12 forms upon acoustic or mechanical excitation, which, through periodic pressure and suction phases, generates a toroidal vortex structure. Resonant coupling 14 between the vortex and the standing wave 12 creates a self-stabilizing flux dynamic 17. The height and intensity of the standing wave 12 can be controlled via the excitation amplitude and the density distribution in the annular resonance cavity 1.

[0041] A matrix of multiple resonator cells can be arranged on a common support surface, allowing their fields to overlap and, depending on the geometry, generate field compression or focusing. The operating mechanism is based on the targeted amplification of both potential fields, with the annular resonance cavity 1 acting as a compression and inward flow, while the central cone 2 generates a directed discharge or outward coupling. The cyclical alternation of inward and outward flow creates a self-stabilizing coupling between the pressure and suction fields, ensuring the stability of the overall system. Brief description of the characters

[0042] The following describes the processes and operating principles of the ring-cone resonator cell depicted in the figures, using an exemplary operating cycle, i.e., active use. In the figures, compression zones 10 of the medium are indicated by dense spot stippling, and negative pressure zones 11 of the medium by sparse spot stippling. Unmarked areas correspond to the normal state of the medium 13 (neither compressed nor decompressed). The flow directions of the medium are indicated by arrows in the figures, with the group of three parallel arrows pointing upwards indicating upward movement and downwards indicating downward movement of the device. The figures are schematic representations intended to illustrate the physical operating principle and are not to scale.The disclosure should therefore not be understood as being limited to the illustrated embodiments, so that it includes differing geometries, materials and excitation types that realize the same mechanism of action. • Fig. 1a - Top view of the classic Helmholtz resonator (state of the art) • Fig. 1b - Sectional view AA of the Fig. 1a (State of the art) • Fig. 2a - Top view of the ring-cone resonator cell (without operating cycles) • Fig. 2b - Sectional view BB of the Fig. 2a • Fig. 2c - Top view of the ring-cone resonator cell (for the working cycles) Fig. 2d-2g) Fig. 2d-2g - Work cycles with phases of downward and upward movement in the sectional view BB • Fig. 2d - Ring-cone resonator cell in downward motion • Fig. 2e - Ring-cone resonator cell in upward motion, continuing to Fig. 2d • Fig. 2f - Ring-cone resonator cell in downward motion, continuing to Fig. 2e • Fig. 2g - Ring-cone resonator cell in downward motion, continuing to Fig. 2f Detailed description of the figures

[0043] The in the Fig. The processes shown in 2c to 2g illustrate that the ring-cone resonator cell generates a cyclic interaction between mechanical movement, pressure distribution and subsequently acoustic resonance.

[0044] The combination of toroidal compression and axial relaxation creates a self-stabilizing vibration field 17 that can both store energy and couple it out into the surrounding medium 13. The field height and intensity are controlled by the amplitude of the excitation. This allows the internal density of the annular resonance cavity 1, and thus the height of the coupled standing wave 17, to be precisely adjusted.

[0045] Fig. Figure 2a shows a top view of the ring-cone resonator cell.

[0046] Fig. 2c shows this same top view for the work cycle in Fig. 2g. In Fig. 2c, Fig. 2g shows the spiral formation of the vortex field 17 within the toroidal ring-shaped resonance cavity 1. The vortex in Fig. 2d forms along the inner walls and guides the medium 13 into a circular motion. In the center of the structure, the rising axis of the standing wave 12 is created, its stability influenced by the internal compression of the annular resonance cavity 1. This top view in Fig. 2c illustrates the spiral self-organization of the medium 13 and the beginning of the resonant coupling 14 between vortex and standing wave 12.

[0047] Fig. Figure 2d shows a cross-sectional view of the resonator cell during the downward movement of the system (three downward-pointing arrows in the lower center of the figure). The system is already at its natural resonance, and a standing wave 12 exists. Due to the downward movement, the medium 13 is compressed towards the center, creating a low-pressure zone 11 at the apex 3 of the cone. From this moment on, the standing wave 12 begins to accumulate mass by converting the kinetic energy of the sound vibration into directed motion.

[0048] Fig. Figure 2e shows the subsequent upward movement of the resonator volume (three upward-pointing arrows in the lower center of the figure). The in Fig. The compressions formed in 2d continue to develop because, due to their inertia, they dissipate more slowly than they form. The upward movement presses the outer medium 13 against the base and the cone apex 3. This pushes the compressed mass axially upwards along the central resonance axis. As the compression in the annular resonance cavity 1 increases, the pressure rises, further centering the flow.

[0049] Fig. Figure 2f shows the subsequent second downward movement. This again generates a large-area negative pressure, which draws the medium 13 into the annular resonance cavity 1. Simultaneously, the previously compressed mass begins to detach slightly from the surface. The pressure-suction interaction intensifies, the medium is cyclically accelerated, and it oscillates between the compression and expansion phases. With suitable excitation, a stable oscillation state is established between a vortex and a standing wave 12.

[0050] Fig. Figure 2g shows the phase in which the compression in the annular resonance cavity 1 reaches its potential. Controlled by the amplitude of the excitation, the accumulated mass falls into the standing wave 12 due to pressure and is accelerated from the inside as an inwardly accelerating medium 15, since it enters the field of action of the standing wave 12 and comes into resonant coupling 14 with it. Due to the continuous mass inflow, the system cannot immediately relax; however, the medium reverses its flow direction and moves against the incoming mass, where it relaxes along the central axis. This creates a self-stabilizing flow dynamic 17 in which pressure and suction fields mutually stabilize each other. The height of the standing wave 12 / 17 is determined by the amplitude – the denser the mass in the annular resonance cavity 1, the higher and more stable the coupled standing wave 17.

[0051] Right in Fig.Figure 2g shows a detail depicting the coupled standing wave 17 in the surrounding structured rising medium 16. This illustrates the transfer of resonance energy from the interior 15 into the outer medium 16 and the beginning of coherent wave formation 17 outside the cell. Example of implementation

[0052] Active excitation by vibration (Contains the detailed phase description, see below under "Description of the figures")

[0053] In a preferred embodiment, the resonator cell is actively excited by vibration, for example by means of a piezoelectric or electrodynamic transducer (e.g. loudspeaker or exciter element).

[0054] A practical implementation consists of a matrix of 19 ring-cone resonator cells, as realized in a field module. Each individual resonator cell is geometrically tuned to a natural frequency of 18 kHz. The inner torus diameter is approximately R = 3.7 mm, and the ring or tube diameter (at the center of the torus ring) is approximately R = 2.3 mm.

[0055] The cells are arranged on a common support plate in a hexagonal matrix. The diameter of the overall matrix is ​​chosen so that the entire surface also acts as a secondary resonant element at approximately 18 kHz natural resonance. This allows the individual fields to superimpose into a coherent overall field with increased stability and energy density.

[0056] To improve conductivity and field coupling, the matrix surface is coated with copper and grounded. This allows the earth's electrical potential to interact with the atmospheric counter-charge, thereby improving field stability and energy absorption from the environment.

[0057] Excitation is achieved with a carrier frequency of 18 kHz, onto which amplitude (AM) and frequency modulation (FM) can be superimposed to selectively vary the field characteristics. This allows for very slow AM modulations below 0.1 Hz as well as variable FM deviations from a few tenths of a hertz up to higher frequency excursions. The modulation parameters can be freely selected depending on the application, medium, and desired field behavior to excite different oscillation and coupling modes of the cells. Commercial applicability

[0058] A commercial application arises particularly from the interaction of the generated vortex fields with fluidic media. The stationary vortex and oscillation field generated by the ring-cone resonator cell can be used to selectively influence the structure and order of liquids, for example, by forming coherent pressure and density patterns in water or other fluids. This effect allows for the modulation of material or energetic properties of liquids—such as conductivity, wettability, or gas exchange behavior. Furthermore, the device can be used in material and surface treatment, sensor and acoustic applications, fluid and plasma modulation, biophysical field excitation, as well as for energy transfer and friction reduction.A concrete commercial implementation is the field module described in the section "Exemplary Design," which comprises a matrix of nineteen resonator cells and was developed for structuring and energetically activating liquids. The system can be manufactured industrially and integrated into laboratory, process, or environmental technology, making the invention immediately commercially viable.

[0059] Sources and representative evidence for the state of the art

[0060] The following documents, patents, and publications represent the known state of the art in the field of acoustic resonators, vortex and transducer structures. They serve to classify the invention within the existing technical environment and are grouped according to application area. 1. Resonator and absorber systems

[0061] US 6782109 B2 (2004) - Electromechanical Acoustic Liner, Boeing / Honeywell - Describes classic aircraft liners with a perforated facesheet, honeycomb core, and rigid rear bulkhead. It serves for sound attenuation via Helmholtz cavities and reflective surfaces; no free or nonlinear field propagation.

[0062] EP 1 860 301 B1 (2008) - Micro-Perforated Acoustic Liner, Airbus / DLR - Micro-perforation cover plate over cellular (honeycomb) structure with backplate; linear absorption system according to Maa principle, not designed for free standing waves.

[0063] US 4 189 027 A (1980) - Sound Suppressor Liners, General Electric - Multi-chamber liner with several Helmholtz cavities for noise reduction in turbines; standing waves only within the cavities, no coupling into the medium.

[0064] US 4 298 090 A (1981) - Multi-Layer Acoustic Linings, Pratt & Whitney - Multi-layer liner with tube and Helmholtz resonators between top and back layers; classic reflection and absorption principle, no free field formation.

[0065] US 10 107 139 B1 (2018) - Acoustic Liners for Turbine Engines, NASA / GE Aviation - Further development of liner structures with curved cells and locally modified cavities; remains limited to reflective Helmholtz mechanics, no toroidal coupling or nonlinearity.

[0066] Maa, DY - Theory and Design of Micro-Perforated Panel Sound-Absorbers, Acta Acustica (1975) / NASA Acoustic Review - Fundamentals of Maa theory; describes linear micro-perforation resonators (MPP) for sound absorption without vortex field or nonlinear effects.

[0067] NASA Technical Review - Characterization of Acoustic Liners (2004), NASA Langley Research Center - Overview of experimental liner characterizations in the linear range; no evidence of toroidal field coupling or nonlinear resonance phenomena.

[0068] CN 110560348 B (2021) - MEMS Piezoelectric Ultrasonic Transducer with Hole-Array Helmholtz Resonant Cavity, Wuhan University (CN) - MEMS structure with hole-array Helmholtz cavities for sound pressure enhancement; shows multiple resonance, but exclusively linear coupling without free field propagation. 2. Piezo and MEMS sound transducers

[0069] EP 3 799 966 B1 (2024) - Acoustic Transducer and Method for Generating / Receiving an Acoustic Wave, TU Darmstadt / Fraunhofer - Thin piezo membrane transducer with rear λ / 2 resonance chamber; reflection principle for sound pressure amplification.

[0070] DE 10 2021 201 784 A1 (2022) - MEMS transducer array, Fraunhofer Gesellschaft (DE) - Array of micro loudspeakers of different resonant frequencies; demonstration of high sound pressures by multi-frequency excitation. 3. Vortex and Focus Transducer

[0071] US 7 273 459 B2 (2007) - Vortex Transducer, LipoSonix Inc. (US) - Ultrasound transducer with shaped vortex structure; generates a ring-shaped focus (annular focus) with a central null. No nonlinear self-coupling effect.

[0072] US 2004 / 0217675 A1- MEMS transducer array, LipoSonix Inc. (US) - Supplementary publication to the above patent; describes focusing high-intensity ultrasound fields (HIFU). 4. Damping and ABH structures

[0073] JASA 2023 - Acoustic Black Hole (ABH) Review, Journal of the Acoustical Society of America - Overview of ABH structures with conical depressions for local energy dissipation.

[0074] Review 2020 - Vibration Energy Concentration in Tapered Plates, Applied Acoustics (Elsevier) - Theoretical foundations of geometric energy absorption, no active field stabilization. 5. Applications in liquids and biological media

[0075] US 9 561 970 B2 (2017) - Audio Device for Altering Water Structure, JT Ling (US) - Acoustic system for exciting water structures; linear sound application without resonator topology.

[0076] US 7 600 343 B2 (2009) - Method of Stimulating Plant Growth, Softwave TRT (US) - Use of focused or divergent shock waves to stimulate biological processes. No ring-cone geometry or free field stability.

[0077] DE 20 2025 001 316 U1 (2025) - Acoustic device for massage or tissue stimulation; superposition of local vibrations on contact surfaces. 6. Sonar and radar systems

[0078] DE 10 2016 004 906 A1 (2016) - Method and device for determining distance or position, J Bosch GmbH (DE) - Use of standing waves for distance measurement; linear reflection, no field stabilization. Reference symbol list 1 Ring-shaped resonance cavity 2 Central cone element 3 Tip of the cone element 4 Axial gap 5 gap width 6 cone angles 10 Compaction zone 11 Low-pressure zone 12 Standing wave (body's natural resonance) 13 Reference state of the medium 14 Resonant Coupling 15 Inwardly accelerating medium 16 Ascending Medium 17 Decoupled standing wave QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 6782109 B2 [0006, 0061] CN 110560348 [0008, 0068] EP 3 799 966 B1 [0013, 0014, 0069] DE 10 2015 100 442 A1

[0017] US 10 900 934 B2

[0017] US 11 946 523 B2

[0017] US 7 273 459 B2 [0019, 0071] DE 20 2025 001 316 U1 [0023, 0077] DE 10 2016 004 906 A1 [0025, 0078] US 6 792 907 B1

[0031] EP 1 860 301 B1

[0062] US 4 189 027 A

[0063] US 4 298 090 A

[0064] US 10 107 139 B1

[0065] DE 10 2021 201 784 A1

[0070] US 2004 / 0217675 A1

[0072] US 9 561 970 B2

[0075] US 7 600 343 B2

[0076] Zitierte Nicht-Patentliteratur

[0000] Broadband Effective Vibration Absorber Using the Acoustic Black Hole Phenomenon

[0017] Li Ma; Li Cheng

[2023] , „Vibration and sound radiation of an acoustic black hole plate immersed in heavy fluid“, in: The Journal of the Acoustical Society of America, J. Acoust. Soc. Am. 154, pp. 179-190

[0017] Maa, D.Y. - Theory and Design of Micro-Perforated Panel Sound-Absorbers, Acta Acustica (1975

[0066] NASA Technical Review - Characterization of Acoustic Liners (2004), NASA

[0067] JASA 2023 - Acoustic Black Hole (ABH) Review, Journal of the Acoustical Society of America

[0073]

Claims

[1] Resonator cell based on the principle of a Helmholtz resonator, consisting of 1.1 a resonance cavity and 1.2 an opening for coupling to a surrounding medium (13), characterized by , that 1.3 the annular resonance cavity (1) is essentially toroidal and has a centrally arranged cone element (2), 1.4 wherein an axially extending gap (4) is formed between the resonance cavity (1) and the central cone element (2), which causes a non-linear coupling between pressure and suction fields, 1.5 wherein the standing wave (12) generated in the resonance cavity (1) is not reflected in the cavity, but propagates stably into the surrounding medium (13) via the gap coupling, 1.6 wherein periodic pressure changes in the gap area result in a continuous energy transfer into the medium (13), so that a free, self-stabilizing vortex and vibration field with a defined axial end is formed (17), 1.7 which enables directed coupling without an external reflector. [2] Resonator cell according to claim 1, characterized by , that the height and intensity of the centrally formed standing wave (12) can be controlled by varying the amplitude of the excitation and the density of the medium (13) enclosed in the resonance cavity (1). [3] Resonator cell according to one of claims 1 or 2, characterized by , that 3.1 the medium (13) is a gas, a liquid, a plasma or a solid with elastic coupling, 3.2 wherein the resonance state is achieved by acoustic, mechanical, electrical, magnetic or piezoelectric excitation. [4] Resonator cell according to one of claims 1 to 3, characterized by , that 4.1 the resonance state is also passively generated by a flowing medium (13), 4.2 wherein the interaction of pressure and suction phases in the gap region (4) creates a standing boundary wave with stable boundary layer formation. [5] Matrix or planar arrangement with a plurality of resonator cells according to any one of claims 1 to 4, characterized by , that the geometry and distance parameters of the individual resonator cells are tuned so that the toroidal fields (17) of the units overlap each other, thereby creating a field density or focusing in space. [6] Matrix according to claim 5, characterized by , that the matrix is ​​lenticularly curved - convex or concave - to concentrate the generated toroidal fields (17) onto a focal point or focal zone. [7] Resonator cell or matrix according to any one of claims 1 to 6, characterized by that the structure is designed for a scalable frequency range from low-frequency to high-frequency components, including coupling to electric or plasmatic fields. [8] Resonator cell or matrix according to any one of claims 1 to 7, characterized by , that 8.1 Geometry parameters such as slit width (5), cavity resonance volume (1), cone angle (6) and cell pitch are varied continuously or sectionwise gradientally, 8.2 whereby the field pattern, frequency position and focus can be specifically controlled through this variation. [9] Resonator cell or matrix according to any one of claims 1 to 8, characterized by , that 9.1 the tip of the central cone element (3) is designed to be interchangeable or geometrically modifiable, 9.2 where it can optionally be designed as a conical, spherical, parabolic or plan-rounded shape, 9.3 and that the surfaces of the resonance cavity (1) and / or the cone element (2) facing the medium are made of an electrically or magnetically conductive material or are provided with a corresponding coating, in particular graphite, copper, silver, gold or aluminium, 9.4 to improve the coupling between the electric and magnetic field components, reduce damping and increase the stability of the standing wave. [10] Use of a resonator cell or matrix according to any one of claims 1 to 9, 10.1 for the formation and stabilization of standing toroidal fields (17) in gases, liquids, solids or plasmas, 10.2 where the use is particularly for material structuring, fluid and plasma modulation, friction reduction, biophysical field excitation or energy conversion.

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