46results about How to "Good calculation stability" patented technology

The invention provides a method for sound field separation by double plane vibration speed measurement and equivalent source method, which is characterized in that a measurement plane S1 and an auxiliary measurement plane S2 parallel therewith and Delta h therefrom are provided in the measured sound field; normal direction particle vibration speed on the two planes are measured; two imaginary source planes S1* and S2* are provided, and equivalent source are distributed on the imaginary source planes; transfer relationship between the equivalent source and normal direction particle vibration speed on two measurement planes are established; strength of each equivalent source on the imaginary source planes S1* and S2* are determined according to the transfer relationship; sound pressure and normal direction particle vibration speed radiated by sound sources on both sides of the two measurement planes are separated according to strength of equivalent source on two imaginary source plane. The invention adopts equivalent source method as the sound source separation algorithm, which has great computation stability, high computation accuracy, and simple implementation; normal direction vibration speed on two measurement planes are used as input for the separation, therefore vibration speed of the separated normal direction particle has high accuracy. The method is widely applicable near-field acoustic holographic measurement under internal sound field or noise environment, material reflection coefficient measurement, scattering sound field separation.

A method of acoustic field separation is disclosed that characterized in that a detecting surface S1 and a auxiliary detecting surface S2 which is parallel with the detecting surface and spaced with the detecting surface by deltah are set in the acoustic field to be detected; The acoustic pressures of the two surfaces are tested; a void source surface S1* and S2* are set, the equivalent sources are spread in the void source surface; the transitive relationship between the equivalent sources and the acoustic pressures of the two surfaces is built; the separation of radiation sound pressure with acoustic sources of the two sides in detecting surface based on the transitive relationship. The measuring surfaces in the invention can be random geometry which contains flat surface, cylindrical surface or spherical surface; the equivalent source method is the sound field separation algorithm, computational stability is well, computational accuracy is high, accomplishment is simple, and the invention can be widely used in the near acoustic field holographic detection of inner acoustic field or in noise environment, the measuring of material reflection coefficient, the separation of scattered acoustic field.

The invention discloses a three-dimensional structure sound source radiation sound field forecast method under the shallow sea channel and belongs to the sound source radiation sound field forecast field. The method is characterized in that firstly, a structure sound radiation multi-physical field coupling model under the shallow sea channel is established, the sea sound propagation theory is selected according to analysis frequency range, calculation distance and shallow sea environment factors to establish a two-dimensional axisymmetric channel transmission function G, through orientation coupling solution development, a channel three-dimensional sound field transmission function is acquired, secondly, the shallow sea channel multi-boundary sound field coupling calculation theory is employed to establish a multi-physical field coupling model, a structure sound source surface speed U under the shallow sea channel under the action of multi-boundary influence is acquired through calculation, and lastly, the Fourier wave superposition method theory is utilized to forecast the sound field information P of a structure sound source at any field point under the channel is forecasted. Themethod is advantaged in that multiple bottleneck problems of high computational complexity, multiple coupling physical fields and complex channel environments existing during researching three-dimensional elastic structure sound source radiation sound field characteristics under the complex shallow sea channel in the prior art are effectively solved.

The invention discloses a pressure speed method sound field separation method, a measured sound field is provided with a measuring surface S; a sound pressure sensor is adopted to measure the sound pressure on the measuring surface S, and a particle velocity sensor or a sound intensity probe is adopted to measure the particle speed on the measuring surface S; both sides of the measuring surface Sare provided with the imaginary source surfaces S1 <*> and S2 <*> which are provided with the equivalent sources; the transfer relationship between the equivalent sources and the sound pressure and the particle speed on the measuring surface S is constructed; the separation of sound source radiation sound pressure and the particle speed of both sides on the measuring surface according to the transfer relationship is realized; the sound field separation is realized by measuring the speed relation of sound pressure and particle on each surface; and the equivalent source method is adopted as thesound field separation arithmetic, the calculation stability is good, the calculation precision is high, and the implement is simple. The method can be widely applicable to the near-field acoustic holography measurement in the environments of internal sound field or noisy sound, the sound intensity method sound source identification in the noisy environment, the material reflection coefficient measurement, and the separation of the scattering sound field.

The invention discloses a method for reestablishing a transient sound field. The method is characterized by comprising the following steps of: setting a holographic surface H in a sound field to be measured, and uniformly distributing M measuring points on the holographic surface H; synchronously measuring sound pressure signals of the M measuring points positioned on the holographic surface H toobtain the time domain sound pressure of the M measuring points by adopting M microphones; setting a virtual source surface S<*> within a sound source surface S, and distributing N time domain equivalent sources on the virtual source surface S<*>; carrying out interpolation processing on the time domain sound pressure of the M measuring points by adopting linear interpolation functions, and establishing the transitive relation between the time domain sound pressure of the M measuring points positioned on the holographic surface H and M time domain equivalent sources at any time; starting to sequentially acquiring the source intensity of the time domain equivalent sources at corresponding times from an initial time; and reestablishing the time domain sound pressure of any field point according to the acquired source intensity of the time domain equivalent sources at all times and the transitive relation between the time domain equivalent sources and any field point. The method disclosed by the invention has the advantages of good computational stability, high accuracy, high speed and easiness for implementation and is especially suitable for reestablishing the transient sound fieldgenerated under the action of transient exciting force.