22 results about "Propeller noise" patented technology

The invention discloses an unmanned aerial vehicle noise elimination method and device for cross-medium direct acoustic communication, and the method comprises the steps: carrying out the sampling of a known detection signal and a receiving signal, obtaining a frequency domain expression, calculating a cross-medium sound pressure transmission function, and extracting amplitude response, phase response and group delay; based on a normalization ratio and local maximum detection method, identifying a center frequency set of unmanned aerial vehicle propeller noise; the notch depth, bandwidth, frequency compensation and phase compensation are determined by combining channel characteristic parameters, and a cascade notch filter is constructed; and inputting the channel characteristic parameters into the deep learning model, outputting a filter parameter correction amount, realizing dynamic updating of the filter, obtaining the filter capable of suppressing noise, and further obtaining a denoised communication signal. According to the invention, precise detection of propeller noise frequency and multi-dimensional adaptive adjustment of filter parameters can be realized.

The invention provides a seismic imaging method and device based on propeller noise, a medium and equipment, and relates to the technical field of marine seismic exploration. The method comprises the following steps: firstly, acquiring seismic data generated by a propeller of a ship in the process that the ship travels according to a preset route, and extracting propeller noise data from the seismic data; then, calculating a sound wave field generated by the propeller based on the propeller noise data, and performing seismic imaging processing based on the sound wave field to obtain a seismic superposition profile map; therefore, marine seismic exploration is carried out by taking the independent ship propeller as a seismic source, and seismic imaging processing is carried out by effectively utilizing noise data generated by the propeller, so that the cost of marine seismic exploration is reduced, and the resolution of seismic imaging is improved.

The invention discloses an analysis and prediction method for high-frequency noise of a pod propeller, and the method comprises the following steps: S1, obtaining flow field original data and corresponding high-frequency noise monitoring data of the pod propeller in a working state, and carrying out the preprocessing; and S2, constructing a flow field-noise coupling analysis framework based on the separation vortex model, and setting a time step length and a calculation frequency matched with actual working conditions. The invention relates to the technical field of ship propeller noise analysis and prediction. According to the pod propulsor high-frequency noise analysis and prediction method, flow field vortex structure characteristics can be captured by constructing a flow field-noise coupling analysis framework and processing the preprocessed flow field data, and the contribution degree of each vortex unit to the high-frequency noise is accurately calculated based on a vortex structure and noise generation correlation mechanism, so that the high-frequency noise analysis and prediction method is provided for the high-frequency noise analysis and prediction of the pod propulsor. The vortex units leading the noise source are screened, dynamic positioning of the high-frequency noise source is achieved by combining the space-time position information of the vortex units, and the source of noise generation can be deeply known.

The invention provides a large and medium-sized water surface ship radiation noise generation and control method, system and device covering a scale effect, and a storage medium, and belongs to the field of large and medium-sized water surface ship radiation noise prediction and analysis. The difference of contribution degrees of machinery, hydrodynamic force and propeller noise to underwater radiation noise in different navigation states is considered, a multi-modal noise separation method is adopted to separate coupling components, and a ship underwater radiation noise source is simplified into a noise source model along a ship body; a ship scale effect analysis and multi-resolution time-frequency analysis technology is introduced, and a generation mechanism of ship radiation noise is simplified into underwater radiation noise caused by shell vibration caused by the fact that a plurality of distributed low-frequency loads act on a ship structure; large and medium water surface ship radiation noise passing characteristic rules are disclosed, and a ship navigation state underwater radiation noise simulation theoretical model is established. According to the method, an effective means is provided for generation and control of underwater noise of the ship, and optimization of ship design and reduction of underwater radiation noise are facilitated.

The invention discloses an underwater propeller blade number identification method based on shaft blade frequency double harmonic search. The method comprises the following steps: (1) collecting an underwater propeller noise signal; (2) calculating the acquired noise signal by using a rapid spectrum-following correlation algorithm to obtain a cyclic spectrum correlation; (3) normalizing the obtained cyclic spectrum correlation to obtain cyclic spectrum coherence, and further constructing an enhanced envelope spectrum by integral average; (4) preprocessing the enhanced envelope spectrum, extracting a line spectrum, and then inputting conditions to carry out peak value search to obtain an alternative axis frequency; (5) inputting detection parameters to construct a search space; and for the combination of each alternative shaft frequency and the blade number, calculating a peak index and obtaining a combination probability table, and finally determining the blade number. The method can reliably extract the propeller blade number characteristics in a complex noise environment, improves the recognition precision, and has important practical application value for target recognition and classification.

This invention relates to the field of passive underwater target identification technology, and in particular to a propeller noise cyclic coherent demodulation method based on an improved real-number genetic algorithm. Based on cyclic stationarity analysis theory, an optimal coherent weighted quadratic envelope spectrum is constructed by replacing the fixed integration frequency band with a weighting function, and an adaptive detection threshold is constructed based on the false alarm probability. The observed spectrum is modeled as the sum of harmonics and noise, and a sparse non-negative optimization problem is solved to extract the harmonics. Using the total harmonic intensity of the envelope spectrum as the cost function, an improved real-number genetic algorithm is used to optimize and search for the optimal weighting coefficient vector. The demodulated spectrum is obtained by coherently weighting and integrating the normalized cyclic modulation spectrum. This invention achieves autonomous allocation of weighting coefficients and adaptive selection of demodulation frequency bands, effectively improving the signal-to-noise ratio gain of cyclic demodulation, and is applicable to passive target identification in data backtracking and review systems.

This invention relates to a method and system for locating coaxial counter-rotating sound sources in rotorcraft, belonging to the technical field of sound source identification methods. It includes: processing the sound pressure signal of the moving sound source using continuous wavelet transform to obtain time-frequency domain variation results; performing Doppler effect correction based on experimental conditions; estimating the spatial location and relative intensity of the noise source using a cross-spectral matrix and weight vector; and performing phase-locked analysis of the rotor noise source intensity using a phase-locked averaging method. This invention differs from traditional time-domain delay superposition algorithms and frequency-domain cross-correlation spectrum methods. It can image unsteady sound sources using time-frequency domain characteristics, solving the acoustic imaging problem of counter-rotating propeller noise and possessing potential applications in the rotorcraft industry.

The invention belongs to the technical field of artificial baits, and discloses a propeller type noise crossed double-hook bait which comprises a mounting shaft, a propeller assembly and double hooks arranged in the propeller assembly in a crossed mode, and the mounting shaft is movably arranged on the upper portion of the propeller assembly; the mounting shaft comprises a first mounting ring; the propeller assemblies include a first propeller assembly and a second propeller assembly. Through the arrangement of the mounting shaft and the propeller assembly, the whole double-hook bait can rotate under the action of water flow in the using process, then noise is generated to better attract fish schools to approach, and the fish catching probability is effectively increased; compared with an existing arrangement mode that a single hook or double hooks are arranged side by side or two hooks are tied on one line, the double-hook cross arrangement has the advantages that grass hanging can be prevented, and the fish catching stability is improved.

This invention relates to the field of ship design and propulsion technology, and discloses a catamaran and its control method. The catamaran includes a hull, with the width direction defined as the direction perpendicular to the catamaran's direction of travel in a horizontal plane. The hull includes a first hull and a second hull arranged symmetrically and at intervals along the width direction, with a channel formed between the first and second hulls along the width direction. It also includes a propulsion assembly disposed in the channel, comprising at least one fin adapted to oscillate to drive the catamaran's movement. This invention solves the problems of high propeller noise, cavitation, and difficulty in towing loads in related technologies for catamarans.

The application discloses a kind of analysis and prediction methods of high-frequency noise of pod propeller, comprising the following steps: S1, obtain the flow field original data and corresponding high-frequency noise monitoring data under the working state of pod propeller, and pre-process;S2, based on the separated vortex model, construct flow field-noise coupling analysis framework, set the time step and calculation frequency matched with actual working condition, the present application relates to ship propeller noise analysis and prediction technical field.The analysis and prediction method of high-frequency noise of the pod propeller, by constructing flow field-noise coupling analysis framework, the pre-processed flow field data are processed, the vortex structure characteristics of flow field can be captured, and based on the correlation mechanism of vortex structure and noise generation, the contribution of each vortex unit to high-frequency noise is accurately calculated, the vortex unit of dominant noise source is screened, and the dynamic positioning of high-frequency noise source is realized in combination with its space-time position information, which helps to understand the root of noise generation.

The invention discloses a propeller noise reduction design method of an eVTOL aircraft and a related device. The method comprises the steps that according to spatial design parameter data, a plurality of spatial design parameter combinations meeting the design requirements of the total lift force requirement and the structural strength requirement of the eVTOL aircraft are obtained; performing distributed propeller system-level noise simulation processing on the propeller design corresponding to each spatial design parameter combination to obtain a system-level noise simulation result corresponding to each spatial design parameter combination; obtaining a first space design parameter combination with the lowest total noise according to a system-level noise simulation result; and performing noise reduction design processing on the propeller in the first space design parameter combination to obtain a propeller noise reduction design result. In the embodiment of the invention, the rapid reconstruction of the full-aircraft noise field is realized, compared with the complete modeling, the calculation amount is obviously reduced, and the time period of the distributed propeller multi-parameter design optimization is shortened.

The utility model relates to a device for reducing submarine propeller noise, submarine hydrodynamic wake flow and submarine thermal wake flow, which comprises a submarine fairing, a support steel beam, an electric control cabinet, a cable connected with a submarine control center, a hydraulic station, a hydraulic pipeline and signal line, a support beam anechoic tile, a connector anechoic tile, a connector bolt and a submarine center control platform. The supporting steel beam is welded to the submarine, the hydraulic station and the electric control cabinet are arranged in the submarine, the fairing is connected with the supporting steel beam through the connector bolts, a cable, a hydraulic pipeline and a signal line which are connected with a submarine control center are connected with the hydraulic station and the electric control cabinet through the interior of the supporting steel beam, and the supporting beam anechoic tile is installed on the supporting beam. The connecting body anechoic tiles are installed at the connecting positions of the connecting body bolts and the supporting steel beams, the flow guide cover is composed of a front body, a middle body, a tail body, a front body foam breaking ring body, a middle body foam breaking ring body, a tail body foam breaking ring body, a hydraulic cylinder assembly, a rotating assembly, a sound absorption wedge and accessories, and a horn mouth structure is arranged at a tail outlet.

The invention discloses a vertical take-off and landing aircraft lift propeller noise reduction method and system, and the method comprises the steps: collecting a noise signal generated by a composite wing eVTOL lift propeller, the current flight state data of an aircraft, and the external environment data, and carrying out the preprocessing of the collected data; extracting spatial features of multi-source noise data on multiple scales by using a CNN convolutional neural network, capturing time sequence features of noise in combination with an LSTM long short-term memory network, and performing weighted fusion on the spatial features and the time sequence features; establishing a hybrid model, optimizing parameters of the hybrid model by using a multi-objective optimization algorithm, inputting the fused noise data into the optimized hybrid model, and generating an optimal noise reduction strategy; and generating a control instruction according to the optimal noise reduction strategy, and controlling the rotation speed and the blade angle of the composite wing eVTOL lift propeller according to the control instruction. Multi-dimensional analysis and noise reduction of propeller noise are achieved, and the noise reduction effect is remarkably improved.

The application provides a paddle, a propeller, a power propulsion device and a ship, and relates to the technical field of propeller noise control, wherein the paddle comprises a blade root, a blade body and a blade tip which are sequentially connected; the blade body has a first pressure surface and a first suction surface which are oppositely arranged, in the process of rotation of the paddle, fluid can flow from the position of the first pressure surface to the position of the first suction surface; at least a part of the blade tip is curved towards the first pressure surface. In the technical scheme of the application, at least a part of the blade tip is curved towards the first pressure surface of the blade body, and this design is beneficial to the structural optimization of the blade tip, can greatly inhibit vortex-induced resonance and reduce noise pollution.

The invention discloses an amphibious vehicle propeller noise control system and method based on PID adjustment, and belongs to the technical field of automobile control, and the amphibious vehicle propeller noise control system based on PID adjustment combines a PID adjustment algorithm with an active noise reduction algorithm, monitors an external environment, adjusts dynamic variable parameters, and improves the noise reduction performance of the amphibious vehicle propeller. The control parameters are converted into propeller control parameters and active noise reduction module control parameters to control noise reduction parameters of an impeller adjusting mechanism and a microphone, and finally noise reduction signals processed through an algorithm are used for sending out reverse sound waves through a loudspeaker to reduce noise in a vehicle.

The invention belongs to the field of signal processing, and particularly relates to a noise suppression method based on UUV motion under a complex noise background. The invention aims to solve the problem that the existing noise processing method is low in efficiency. According to the noise suppression method based on UUV motion under the complex noise background, the sound source positions and arrays of propeller noise and vibration noise are relatively unchanged in the steering period of the UUV, and the incident angle of a signal changes along with the course angle of a platform. If the environmental noise is kept stable, the noise shows the characteristic of being stable and unchanged during steering, and the signal shows the characteristic of changing along with the course angle. According to the method, the difference between the signal covariance and the noise covariance is utilized, changing signals are filtered out in the frequency domain, and the noise covariance is estimated. And then noise suppression is carried out by using the estimated noise covariance, so that detection in a complex noise environment is further realized, and the problem of low efficiency of an existing noise processing method is solved.

This invention discloses a method for simulating radiated noise signals from a counter-rotating propeller target, comprising: First, setting basic parameters of the counter-rotating propeller target, including simulation time, simulation harmonics, and signal-to-noise ratio (SNR). Second, setting signal parameters of the counter-rotating propeller target under stable navigation conditions, including noise fundamental frequency and frequency fluctuation variance, and setting signal parameters of the counter-rotating propeller target under maneuvering conditions, including maneuvering time and fundamental frequency increment. Third, generating signal frequency curves based on the signal parameters of the counter-rotating propeller target under stable navigation and maneuvering conditions. Fourth, calculating the signal phase point by point based on the counter-rotating propeller target signal frequency curves to generate a simulated counter-rotating propeller noise line spectrum signal. Fifth, adding noise according to the SNR and summing the results to generate a simulated counter-rotating propeller target noise signal. This method can accurately describe the time-varying frequency characteristics under different conditions, ensuring phase continuity and time-frequency consistency.

This invention provides a method and system for mathematical noise cancellation of propellers based on FFT. It involves processing the time-domain signal data of propeller noise using FFT to obtain a frequency-domain signal. This frequency-domain signal is then plotted as a spectrum with frequency on the horizontal axis and sound pressure level on the vertical axis. The spectrum is used to determine whether a singing tone exists within the frequency-domain signal of the propeller noise. If a singing tone is present, it is categorized into three types based on its influence range and position within the full frequency band of the spectrum: Type I, Type II, and Type III. Different judgment and calculation methods are then used to eliminate the singing tone in each of these three types, thus completing the noise cancellation of the propeller. This invention does not require time or financial costs to modify the propeller model, nor does it require changing the rated operating conditions in the original experimental plan.

This invention belongs to the field of vertical takeoff and landing (VTOL) aircraft technology, specifically relating to a noise-controllable VTOL aircraft propeller design method and implementation device. The design method includes steps such as selecting key positions in the blade spanwise direction and determining the basic airfoil, optimizing the airfoil at the key positions, constructing a preliminary propeller configuration, investigating the influence of chord length, negative torque, and blade number on noise, determining the basic propeller configuration and optimization range, and optimizing the propeller aerodynamic performance. This method starts with optimizing the airfoil at the key positions of the blade, gradually investigating the influence of chord length, negative torque, and blade number on propeller noise, determining the basic propeller configuration and optimization range with acceptable noise, and performing multi-objective aerodynamic optimization based on this. This improves the aerodynamic efficiency of the propeller, reduces the noise level, and reduces trial and error costs and time. It can provide a high-performance, low-noise propeller design scheme for VTOL aircraft, meeting their application needs in complex environments such as urban air traffic.

The application discloses a kind of underwater vehicle propeller noise fast prediction method, device, medium and program based on excitation source reconstruction, belongs to noise prediction technical field.The method of the present application is based on the invariance of vibration transfer function relationship and the basic theory such as sound energy superposition principle, vibration source reconstruction technology is introduced into propeller noise prediction, to the vibration response measured and obtained by a plurality of vibration sensors on the stern structure of propeller as input, based on vibration transfer function reconstruction excitation source matches structure surface vibration, by the excitation source reconstructed, the radiation noise caused by the structure vibration of propeller shaft boat structure vibration generated by structure vibration can be solved;Establish the propeller direct sound fast prediction method under different coherence, based on energy superposition principle realizes including propeller shaft boat coupling noise and propeller direct sound propeller noise fast prediction evaluation.The present application is suitable for ship real-time monitoring propeller shaft vibration and radiation noise.

The invention discloses an intelligent hydrofoil noise reduction device and method based on reinforcement learning, and belongs to the technical field of propeller noise reduction. The intelligent hydrofoil noise reduction device comprises a propeller, the propeller is connected with a control box and installed in a transparent water tank, and the control box is used for adjusting the rotating speed and the incoming flow speed; the intelligent hydrofoils are connected with the propellers, telescopic devices are mounted in the hydrofoils, the telescopic devices change the hydrofoil mounting spacing ratio and the hydrofoil length, and propeller hub rings for changing the circumferential mounting positions are mounted at the roots of the intelligent hydrofoils; the arrays of the pressure sensors are installed on the surface of the propeller hub ring and the surface of the intelligent hydrofoil respectively and used for collecting unsteady pressure pulsation data, and the pressure sensors are connected with the data center. And the active control system adjusts the optimal vortex reduction angle of the hydrofoil under the current working condition so as to realize efficient self-adaptive noise reduction. The method can effectively weaken the propeller hub vortex, improve the flow field structure, obviously reduce the propeller noise, reduce the dependence on physical experiments, improve the optimization efficiency and reduce the cost.

The application discloses a UAV noise cancellation method and device for cross-medium direct acoustic communication, and the method comprises the following steps: sampling a known probe signal and a received signal, obtaining a frequency domain expression, and calculating a cross-medium sound pressure transmission function to extract an amplitude response, a phase response and a group delay; based on a normalized ratio and a local maximum value detection method, a center frequency set of a UAV propeller noise is identified; a notch depth, a bandwidth, a frequency compensation and a phase compensation are determined in combination with channel characteristic parameters to construct a cascaded notch filter; channel characteristic parameters are input into a deep learning model to output a filter parameter correction amount, dynamic updating of the filter is realized, a filter capable of suppressing noise is obtained, and a communication signal after noise reduction is obtained. The application can realize accurate detection of propeller noise frequency and multi-dimensional adaptive adjustment of filter parameters.