494 results about "Pressure wave" patented technology

The invention discloses a water supply pipe network water hammer control method and system based on multifunctional module fusion, and relates to the technical field of data identification. A time sequence diagram neural network prediction and traceability module which realizes water hammer risk prediction and propagation path traceability based on a causal constraint graph neural network model; the reinforcement learning intervention decision module is used for generating an active intervention strategy through a reinforcement learning agent, forming closed-loop control, abstracting a water supply pipe network into a graph structure, and modeling in combination with a time sequence, so that a propagation path of pressure waves can be comprehensively reflected, a blind area of traditional local modeling is overcome, and the comprehensiveness and accuracy of water hammer event detection are improved; and a causal analysis result is input as an adjacent matrix, so that the interference of irrelevant edges on prediction in topology is effectively eliminated, and the learning efficiency and causal traceability of the model are improved.

The invention relates to the technical field of non-electrical variable control, and discloses an industrial water chiller temperature intelligent adjusting system, which comprises a refrigeration circulation loop and a control unit, the control unit calculates a steady state control component based on the water outlet temperature deviation, performs differential processing on the refrigerant pressure to extract the gradient, and outputs the gradient. Generating a transient compensation component when the gradient exceeds a dynamic noise threshold; according to the method, the problem of thermal lag is solved by utilizing the pressure wave transmission speed advantage, aggressive response is prevented from triggering low-pressure shutdown through a safety margin constraint mechanism, the pressure safety margin is calculated in real time, a gain coefficient is determined according to a nonlinear model, and a final driving instruction is generated. And the dynamic balance of the control response speed and the system physical security boundary is realized.

The invention discloses an experimental device and an experimental method for combustible gas explosion discharge of a communicating container, and belongs to the field of combustible gas explosion protection. The experimental device comprises a communicated discharge container, a gas distribution system, a high-voltage ignition system, a data acquisition system, a high-speed schlieren system and a synchronous control system. The experimental device and the experimental method can be used for experimental research on combustible gas explosion release of the communicating container; the influence rules of factors such as static action pressure (Pstat), discharge caliber (Dv), discharge coefficient (Kv), spherical explosion container volume ratio (V1 / V2), communication pipeline length (L), communication pipeline diameter (D), fuel gas equivalence ratio (phi), ignition position (IIn) and ignition energy (E) on flammable gas explosion discharge overpressure and discharge flame are analyzed; and the formation factors of internal and external discharge overpressure peak values (a peak value Pb formed by rupture of a discharge diaphragm, a peak value Pex formed by external secondary explosion, a peak value Ph formed by Helmholtz oscillation, a peak value Pac formed by sound wave coupling and a peak value Pred formed by a maximum flame area), a discharge gas cloud structure, a discharge flame form and an external pressure wave evolution rule are explored.

The invention discloses a BIM (Building Information Modeling)-based large-span post-tensioned bonded prestressed beam construction method. The BIM-based large-span post-tensioned bonded prestressed beam construction method comprises the following steps: collecting a vibration signal of a working rib and a matt rib reference signal of a matt rib; inputting the dummy rib reference signal into an adaptive filtering algorithm to which phase preserving constraint is applied, and performing noise cancellation processing on the working rib vibration signal to generate a purified pressure wave signal; performing multi-scale decomposition on the purified signal, extracting propagation time delay of the direct wave based on coherence analysis among components, and generating a phase-time delay characteristic matrix; and based on pre-configured geometric parameters of the BIM three-dimensional model, a real-time stress distribution field is calculated through inversion according to the phase-time delay characteristic matrix, and the real-time stress distribution field is synchronously updated to the BIM three-dimensional model. According to the method, the phase distortion problem under noise interference is solved through a physical reference channel and phase preserving filtering, the accuracy of time delay extraction is improved through a multi-path separation technology, and high-precision and high-robustness real-time monitoring of the prestress is achieved.

The invention provides a method for testing flow-induced noise of a pipeline. The method comprises the following steps: S1, determining measurement positions at an upstream flow channel and a downstream flow channel of a measured element, carrying out normalization processing on measured signals, and calculating the pressure power spectrum density of the inner wall surface of a pipe; s2, calculating a wall surface pressure fluctuation time domain cross correlation coefficient, and analyzing correlation characteristics between wall surface pressure pulsation; s3, spectrum intrinsic orthogonal decomposition is carried out on the pressure pulsation field, and space-time decoupling is achieved through time domain-frequency domain conversion; s4, extracting a dominant flow-induced noise mode, constructing an empirical frequency-wave number spectrum, and decomposing fluctuating energy distribution into contributions of different frequency and wave number combinations; s5, analyzing the decoupled flow-induced noise characteristic result, and identifying the amplitude-frequency characteristic of the flow-induced noise; according to the invention, real-time measurement of pressure pulsation in the pipeline can be realized, decoupling analysis of flow field pulsation and sound pressure pulsation can be carried out on the measured signal, and characteristics and a generation mechanism of pipeline flow-induced noise can be identified.

The invention discloses a pure electric vehicle heat pump type whole vehicle thermal management system and method, and relates to the technical field of new energy vehicle thermal management, and the method comprises the following steps: constructing a combined twin system of thermal fluid, structural vibration and acoustic fluctuation, collecting pressure waves and vibration phases by using an array sensor, forming a steady state baseline spectrum and a transient state baseline spectrum, and calculating the temperature of the steady state baseline spectrum and the transient state baseline spectrum; and a unified reference is established. According to the method, a combined twinborn system of thermal fluid, structural vibration and acoustic fluctuation is constructed, the dynamic characteristics of pulsating waves are accurately monitored, and instability early warning is carried out by using a phase locking tracking method. Through pipeline topology reconstruction and segmented damping link design, a self-adaptive pulsation buffer zone is introduced, and pulsation energy is effectively absorbed. And in combination with a multi-target control law and a time reflection mirror cooperative regulation strategy, refrigerant flow is accurately controlled, pulsation energy is actively counteracted, and stable operation of the system is guaranteed. Through the innovative design, the stability of a heat management loop is improved, the fault risk caused by pulsation is reduced, and the cooling efficiency and safety are improved.

A bi-directional photoacoustic gas sensor includes a first photoacoustic cell, where an electromagnetic radiation source emits radiation to interact with an external gas and generate pressure waves that are detected by a MEMS diaphragm. A second photoacoustic cell has an interior volume and acoustic compliance that corresponds to the interior volume and acoustic compliance of the first photoacoustic cell. Processing circuitry within a substrate uses a first acoustic signal, received by the first photoacoustic cell, and a second acoustic signal, received by the second photoacoustic cell, to determine a bi-directional response of the gas sensor to remove noise and improve the sensor's signal-to-noise ratio.

The utility model relates to the field of fuel gas pressure regulation, in particular to a double-layer noise reduction valve cage and a regulating valve, which comprises an inner-layer valve cage, a plurality of first noise reduction holes, a second-layer valve cage and a third-layer valve cage, the outer-layer valve cage is arranged outside the inner-layer valve cage in a sleeving manner and fixedly connected with the inner-layer valve cage, and a plurality of second silencing holes which are arranged according to a second rule are formed in the outer-layer valve cage; and the inner-layer valve cage and the outer-layer valve cage are coaxially arranged. According to the utility model, the inner-layer valve cage is used for preliminarily dispersing pressure waves and noise of fluid through the plurality of first silencing holes arranged according to the first rule, the outer-layer valve cage is used for further absorbing and scattering residual noise generated by the inner-layer fluid through the second silencing holes, and the inner-layer valve cage and the outer-layer valve cage are coaxially arranged; the additional flow resistance generated when fluid penetrates through different layers can be reduced, and meanwhile the continuity of a flow channel is guaranteed. Under the conditions of high pressure difference and large flow, noise of the regulating valve is effectively reduced, it is ensured that the noise level does not exceed 85 decibels, and the requirements of specific application occasions are met.

An acoustic matching structure is used to increase the power radiated from a transducing element with a higher impedance into a surrounding acoustic medium with a lower acoustic impedance. The acoustic matching structure consists of a thin, substantially planar cavity bounded by a two end walls and a side wall. The end walls of the cavity are formed by a blocking plate wall and a transducing element wall separated by a short distance (less than one quarter of the wavelength of acoustic waves in the surrounding medium at the operating frequency). The end walls and side wall bound a cavity with diameter approximately equal to half of the wavelength of acoustic waves in the surrounding medium. In operation, a transducing element generates acoustic oscillations in the fluid in the cavity. The transducing element may be an actuator which generates motion of an end wall in a direction perpendicular to the plane of the cavity to excite acoustic oscillations in the fluid in the cavity, and the cavity geometry and resonant amplification increase the amplitude of the resulting pressure oscillation. The cavity side wall or end walls contain at least one aperture positioned away from the center of the cavity to allow pressure waves to propagate into the surrounding acoustic medium.

The invention relates to the technical field of logging, and discloses a logging-while-drilling mud pressure wave signal processing method and system, a terminal and a medium, and aims at acquiring noise signals of a mud pump, performing Fourier transform, determining working frequency band characteristics of the mud pump, acquiring and performing Fourier transform during pressure wave signal transmission, and determining current working frequency band characteristics. On the basis of the comparison result of the characteristics of the two sections of frequency bands, a proper filter is determined, quantitative and accurate filtering of noise signals is achieved, and the characteristics of original pressure wave signals are effectively recovered. The noise frequency band characteristic of the mud pump signal is determined by accurately analyzing the frequency band characteristic of the mud pump signal, and the recovery of the pressure wave signal is realized by combining the frequency spectrum characteristic of the pressure wave signal and based on the design and selection of a band-pass / band-stop filter; according to the signal processing method, noise filtering is carried out based on actual parameter adjustment to replace original experience-based setting, so that an engineer can rapidly debug instrument parameters based on operation parameters, and the instrument debugging time is shortened.

The invention relates to the technical field of wave concentrators, and discloses a cavitation wave concentrator which comprises a connecting pipe, one end of the connecting pipe is fixedly connected with an adjusting pipeline, one end of the adjusting pipeline is fixedly connected with a cavitation generator, water flow is conveyed from the A direction to the B direction in a resonant cavity, and the water flow is conveyed in the cavitation generator. Water flow is accelerated and local pressure is reduced through the cavitation generation pipe, so that bubbles are induced to be formed and tiny bubbles are manufactured, pressure waves generated by the resonant cavity are spread in fluid in the form of sound waves and are finally reflected and focused through the arc-shaped wave gathering opening, a high-pressure, high-temperature and high-energy gathering area is generated, and the bubbles fully grow up in the area. Grown bubbles are rapidly annihilated when encountering microorganisms through water jet, so that huge impact force and shear force are generated, and barnacles at the bottom of the ship are efficiently washed away in water. According to the device, efficient impact force is achieved through the pressure wave gathering effect and the cavitation effect, then barnacles and other attachments at the bottom of the ship can be easily removed, and the effect is better.

The invention discloses a pump turbine phase resonance risk identification method and device, a medium and a product, and relates to the field of hydroelectric generation. The method comprises the following steps: firstly, carrying out a pressure pulsation test on the water-turbine generator set to determine each-order dominant frequency of an excitation source; calculating the wavelength of a pressure wave corresponding to each order of dominant frequency according to the working condition of the pump turbine; according to the working condition of the pump turbine, the position difference of two pressure wave transmission during two adjacent excitation is calculated; substituting the wavelength of the pressure wave corresponding to the dominant frequency of each order and the position difference under different pump turbine working conditions into a phase resonance risk coefficient calculation formula, and calculating to obtain a phase resonance risk coefficient of the pressure wave corresponding to the dominant frequency of each order; and comparing the phase resonance risk coefficient of the pressure wave corresponding to the dominant frequency of each order with the risk judgment coefficient, and identifying the harmonic order with the phase resonance risk. By adopting the method, the judgment precision of phase resonance can be improved, and the application range of the phase resonance judgment method is expanded.

The invention discloses an elastic material hydrofoil fluid-solid coupling cavitation erosion forecasting method based on a potential energy theory, and belongs to the field of computational fluid mechanics and cavitation. The implementation method comprises the following steps: simulating the cavitation of the hydrofoil made of the elastic material by using a tight coupling algorithm to obtain the pressure and steam volume fraction distribution of the surface of the hydrofoil; a steam volume fraction distribution based on pressure; constructing an erosion index correction factor F for representing the bending torsional deformation degree of the elastic material hydrofoil to correct the cavitation erosion index represented by the pressure wave power density; the cavitation erosion indexes larger than a threshold value are screened out, and the final cavitation erosion risk index is a quotient after superposition of the cavitation erosion indexes; the corrected cavitation erosion index data are interpolated into RGB color data, the data serve as a geometric structure model of a fourth-dimensional mapping elastic material hydrofoil, and the corrected cavitation erosion index numerical value is represented through color change. The corrected cavitation erosion index can more accurately forecast a cavitation erosion risk part on the surface of the hydrofoil made of the elastic material.

A method is described for generating high-resolution images of transversely isotropic mechanical properties and attenuation properties of tissues associated with measured compressional waves. A pressure wave is transmitted to a region containing fibers that are oriented with transverse isotropy. Waves are received that propagate after the pressure wave has impinged upon the fibers. An initial velocity and attenuation model is created that takes into account the transverse isotropy of the fibers. Full Waveform Inversion (FWI) is used to iteratively minimize a difference between the received data and the initial velocity and attenuation model to create an image of the region that takes into account the transverse isotropy of the fibers. The image has a higher resolution than if created using the initial velocity and attenuation model.

The present disclosure relates to a reverse-time migration method for marine vertical cable seismic (VCS) survey data and provides a reverse-time migration apparatus and method for vertical cable seismic (VCS) survey data using directional propagation of receiver wavefields, configured to perform equation-of-motion-based transform and inverse-transform processing on observed pressure wavefields during back-propagation of receiver wavefields to solve the problem of reflection boundary screening due to long-wavelength artifacts and avoid up / down wavefield separation to thereby simplify a migration process and improve overall quality of migration images.

The invention discloses a transformer arc fault equivalent test device and a control method, and relates to the technical field of power equipment fault simulation and safety test, and the method comprises the steps: carrying out the corresponding high-pressure gas storage through a high-pressure gas storage unit according to target pressure data calculated by a choking flow dynamic coupling model; the quick release unit is used for matching fault duration according to the test trigger instruction so as to release the high-pressure gas stored in the high-pressure gas storage unit; the energy injection unit injects high-pressure gas into the test oil tank to form shock waves; the safety protection unit starts an interlocking protection mechanism based on the test data; the monitoring control unit controls each unit to act, monitors the operation process of each unit in real time, and obtains and identifies the validity of test data to optimize the test process; according to the invention, automatic test process control is realized, the arc fault key damage effect can be accurately quantified and reproduced, high-precision matching of pressure wave time domain characteristics is realized, and the reliability of a test result is ensured.

The invention relates to the technical field of municipal engineering, in particular to a water supply network pipe burst positioning method, device and equipment and a storage medium. According to the water supply network pipe burst positioning method provided by the embodiment of the invention, the moment when the pipe burst pressure wave reaches each monitoring point is determined through the high-frequency pressure monitoring data, the possible pipe burst position is delineated on the basis of the moment and the propagation time of the transient flow pressure wave, and then the transient flow pressure data at each monitoring point are simulated and calculated on the basis of the transient flow model. And through considering the continuous change information of the pressure wave, the simulated transient pressure data is matched with the high-frequency monitoring data, so that the pipe explosion position can be accurately positioned from the possible pipe explosion positions. Therefore, the problem that the positioning result is easily influenced by the wave velocity estimation error due to the fact that the pipe explosion position is positioned only based on the time difference of the transient pressure wave reaching each monitoring point in the prior art is solved.

Acoustic sensors with one or more microlens structures, as well as methods for fabricating and operating such acoustic sensor systems are disclosed. In some embodiments, an apparatus may include: an acoustic sensing element; a display stack; a first layer of material having a first acoustic refractive index and one or more microlens structures disposed at a first surface of the first layer of material; and a second layer of material disposed on the first layer of material and the one or more microlens structures, the second layer of material having a second acoustic refractive index that is different from the first acoustic refractive index. The one or more microlens structures may be configured to form a focused pressure wave from one or more acoustic signals emitted by the acoustic sensing element.

The invention discloses a numerical method for evaluating a high-speed train head type relieving tunnel micro-pressure wave effect. The optimization method comprises the following steps: establishing a three-dimensional geometric model of a full-size three-marshalling train; establishing geometric models of the tunnel and the background area, wherein the tunnel portal shape is a portal shape without a buffer structure and a portal shape with a buffer structure; carrying out grid division and physical model setting on the geometric models of the train and the tunnel by utilizing computational fluid mechanics software, simulating a process of generating an initial compression wave when the train enters the tunnel by utilizing an overlapping grid method, and carrying out grid independence verification and numerical method verification; simulating the tunnel entering process of different train head types; according to the flow field characteristics in the tunnel and the pressure monitoring point data, determining and forming a complete initial compression wave waveform position; and comparing the initial compression wave shapes and the pressure gradient amplitudes of different head shapes, and evaluating the effect of each high-speed train head shape in the aspect of relieving the tunnel micro-pressure wave effect. The maximum pressure gradient value of the initial compression wave generated when the high-speed train drives into the tunnel can be accurately predicted, the flow field is simple, the grid design is reasonable, and the calculation time can be greatly saved.

A device for generating pressure waves of high amplitude, in particular for boiler cleaning, has a pressure-resistant container (21, 40) with a combustion chamber (121) inserted therein, which can be filled with a flowable burn-off material via supply lines. The pressure-resistant container has a discharge opening (306) for the directional discharge of gas pressure generated by ignition of the combustible material. A piston (70) closes the discharge opening, can release it for directional discharge and can be pushed back into the initial position by a spring device. With respect to its longitudinal direction (305), the seat of the piston (70) has a piston surface (302) inclined obliquely to the discharge opening (306), which is arranged opposite a housing surface (303) also inclined obliquely to the discharge opening (306), the housing surface (303) opening opposite the piston surface (302) at an angle (304) oriented towards the discharge opening (306) from a closure line (65) oriented perpendicularly to the piston direction (90).

The invention relates to the field of high-speed railway tunnel aerodynamics, in particular to a high-speed railway tunnel transient pressure wave efficient generator based on a harmonic synthesis method, which comprises a transient pressure wave generation module, a data pre-processing module, a core processing module, a transient pressure wave output module and a target experiment model, the transient pressure wave generation module generates a positive pressure waveform and a negative pressure waveform; the data pre-processing module is used for calculating characteristic data of field test pressure waves; the core processing module adopts a harmonic synthesis method to reconstruct pressure wave data, and sends pressure wave time history data to the transient pressure wave output module to generate positive pressure waves and negative pressure waves; and the transient pressure wave output module is connected with the core processing module and is used for outputting the positive pressure wave and the negative pressure wave to a target test model. The generator can efficiently simulate pressure waves under various driving conditions, and time-frequency information of actual pressure waves is reserved, so that the test efficiency and precision are improved.

Devices and methods are disclosed for monitoring at fishing vessels to detect blast fishing activity. A blast sensor is mountable to a vessel such that it produces a signal in response to pressure waves in water. A controller receives the signal and is operable to analyze the signal to detect blast events based on signal characteristics. A position measurement device measures a position of the vessel. A transmitter is provided to wirelessly transmit status information including a unique identifier of the monitoring unit and indicative of the position of the monitoring unit and to send a wireless alarm signal in response to a detected blast event.

The invention discloses an electric forklift gantry synchronous inclination system and an inclination system control method, and relates to the technical field of vehicle engineering and electrical control, and the method comprises the following steps: establishing a time-frequency phase-locked observation baseline, and calibrating an abnormal trigger window by collecting a pressure wave change track of the gantry synchronous inclination system under a reverse pressure bearing condition; generating a pressure wave characteristic fingerprint and a time delay matrix as dynamic references for resonance path identification; and according to the pressure wave characteristic fingerprints and the time delay matrix, inverting a hydraulic pipeline reflection topology, identifying a pressure energy concentration area, extracting a resonance source anchor point, constructing a wave energy distribution diagram, and forming a space positioning basis of the standing wave risk. According to the method, hydraulic standing wave risk modeling and boundary extraction are achieved through time-frequency observation and resonance path recognition, a standing wave damping structure is constructed in combination with the phase conjugate test and track shaping technology, steady-state damping and high-precision synchronous inclination control of the portal under reverse pressure bearing are achieved, and the system stability and operation safety are improved.

The invention relates to the technical field of metal hot working, and discloses a metal heat treatment nitriding process, and a management method of the metal heat treatment nitriding process comprises the following steps of S1, metal preparation, S2, nitriding treatment, S3, annealing, quenching and tempering treatment, S4, metal surface post-treatment and S5, metal detection and analysis. The machining precision and the surface quality can be effectively improved for curved burrs of metal materials, narrow pulse width and high pulse frequency are used in the machining process, due to the gap effect and the step change of pulse current, an electrolyte in a machining gap oscillates, pressure waves are generated, and the machining precision and the surface quality are improved. The stirring effect of the pressure waves improves the flowing condition of the electrolyte in the machining gap, accelerates updating of the electrolyte in the machining gap and eliminates nonuniformity of conductivity distribution of the electrolyte in the machining gap, so that the machining precision and the surface roughness are improved, and the subsequent nitriding fineness of metal is improved.

The invention relates to the technical field of high-speed railway tunnel aerodynamics, in particular to a railway tunnel micro-pressure wave pneumatic analysis and evaluation management system which comprises the following steps: S1, speed verification: acquiring the current train speed; s2, track type judgment: obtaining the track type of the tunnel; s3, tunnel length judgment: obtaining the tunnel length; s4, micro-pressure wave evaluation: calculating a micro-pressure wave peak value, comparing the micro-pressure wave peak value with a control standard, and judging whether the micro-pressure wave peak value meets the standard or not; s5, mitigation measures: when the micro-pressure crest value exceeds the standard, adopting the mitigation measures, and updating the input parameters to perform modeling simulation and evaluation again; and S6, outputting a result: generating a report. According to the method, the automation level and the intelligent degree of tunnel pneumatic safety design are effectively improved, and the risk of environment and safety problems caused by micro-pressure waves is reduced.

The invention relates to the field of high-speed railway tunnel aerodynamics, in particular to a tunnel train-induced pressure wave refined generation device based on short-time Fourier transform, a positive and negative pressure generation module is used for generating positive pressure waves and negative pressure waves generated when a high-speed train passes through a tunnel; the central control module is connected with the positive and negative pressure generation module, and the central control module is used for generating pressure waves with the same frequency as the tunnel field transient pressure waves and controlling the generation frequency, intensity and duration of the pressure waves through a short-time Fourier transform program; and the pressure wave output module is connected with the central control module and is used for outputting the generated positive pressure wave and negative pressure wave to a target test model. The system has the advantages of being high in automation degree, high in adaptability and wide in practicability, accurate simulation can be conducted according to different tunnel structures and working conditions, and scientific support is provided for tunnel design and train operation safety.

The invention relates to the technical field of immersed roadbed simulation, in particular to an immersed roadbed simulation test system and method for repeated seepage based on load action, and the system comprises a dynamic water pressure gradient generation subsystem, a stress seepage coupling response cavity subsystem and a seepage stability loss early warning network subsystem. The method comprises the following steps: forming a time-space alternating water pressure gradient field on a permeable medium substrate by a wave front of programmable pressure waves; introducing the water pressure gradient field into a three-way independent loading frame; asymmetrical cyclic stress waves are applied to the roadbed sample through the piezoelectric lattice array, and meanwhile the transient hydraulic impedance spectrum of pores in the sample is captured in real time; inputting the local strain energy density distribution and the pore dynamic water pressure pulsation intensity into a chaotic feature extractor, and outputting a structure degradation energy entropy value; and when the structure degradation energy entropy value breaks through the phase change threshold value, three-stage early warning is triggered. Controllable experimental conditions and quantitative evaluation means are provided for studying the progressive failure mechanism of the immersed roadbed under the action of repeated seepage-load coupling.

The invention discloses a high-frequency water hammer pressure wave monitor suitable for fracturing, and relates to the technical field of water hammer pressure monitoring, the high-frequency water hammer pressure wave monitor comprises a shell, and the inner wall of the shell is sequentially provided with a buffer pad, a communication power supply module, a data acquisition and processing module, a signal adjusting and filtering module and a pressure detection module from top to bottom; a filter screen is fixedly connected to the lower side of the inner wall of the shell, and a vibration sensing module and a temperature collecting module are arranged between the pressure detection module and the signal adjusting and filtering module. By arranging the pressure detection module, the signal adjusting and filtering module, the data acquisition and processing module, the communication power supply module, the buffer pad, the vibration sensing module and the temperature acquisition module, a complete pressure acquisition, signal conditioning, data processing and transmission system is constructed, and the system has anti-seismic compensation and temperature correction functions; the system improves the monitoring precision and the system stability, is high in practicality, and is suitable for the real-time monitoring demands under the working condition of high-frequency water attack.

The invention relates to the technical field of natural gas hydrate reservoir permeability monitoring, in particular to a hydrate underground permeability monitoring device. A hydrate underground permeability monitoring device is characterized in that the hydrate underground permeability monitoring device comprises a sealing shell, a pressure system, a fluid isolation system, a control and data processing system, a detection system and a plurality of valve bodies, detecting a pressure value in the test section through the detection system, adjusting the pressure value in the test section through the pressure system so as to disturb the pressure in the test section, and obtaining a pressure change curve through the change of the pressure value so as to calculate the permeability of the hydrate reservoir. The problems that in the prior art, when a cable formation test is conducted, the pressure reduction capacity is insufficient, the influence range of pressure waves is small, and the obtained permeability result is inaccurate are solved.

The invention relates to a forward prediction method for bubble pulsating pressure wavelets in a shallow water area, belongs to the field of deep sea resource exploration and ship structure protection, and aims to solve the problem of forward prediction of bubble pulsating pressure in the shallow water area in existing engineering. The method comprises the steps of inputting bubble initial conditions, environmental parameters and pressure measuring point positions, judging the influence of a water area boundary, designing a correction term expression, substituting into an equation to carry out time advance, calculating and considering physical quantity propagation time, and finally outputting a pressure curve based on a Bernoulli equation. On the basis of the Kelvin impulse theory, buoyancy parameter deviation induced by non-spherical deformation of the bubbles is corrected, the Kelvin impulse theory solution of the large-scale bubbles under the influence of different water area boundaries is calculated through the mirror image bubble method, and the purpose of rapidly predicting the jet flow direction of the underwater large-scale bubbles is achieved. And a theoretical basis and a basic technical support are provided for engineering construction.