Near-field acoustical holography (NAH) is a powerful tool for identifying noise sources and visualizing acoustic field. By recording the acoustic pressures in the near-field, the acoustic quantities in the whole 3-D f...Near-field acoustical holography (NAH) is a powerful tool for identifying noise sources and visualizing acoustic field. By recording the acoustic pressures in the near-field, the acoustic quantities in the whole 3-D field can be reconstructed and predicted. However, the current theory of NAH is not applicable to tracking large scale moving noise sources. Therefore, the hybrid near-field acoustical holography is developed for reconstructing acoustic radiation, which is derived from statistically optimized near-field acoustical holography (SONAH) and moving frame acoustical holography (MFAH). The theoretical formulation is systematically addressed. This method enables us to visualize the noise generated by moving noise sources and the measurement array can be smaller than the source, which improves the practicability and efficiency of this technology. Numerical simulations are presented to demonstrate the advantages of hybrid NAH. Then, two experiments have been carried out with a line array of hydrophones. The results of simulations and experiments support the proposed theory, which shows the advantage of hybrid NAH in the reconstruction of an acoustic field in an underwater holographic measurement.展开更多
One-step patch near-field acoustical holography(PNAH) is a powerful tool for identifying noise sources from the partially known sound pressure field.The acoustical property to be reconstructed on the surface of intere...One-step patch near-field acoustical holography(PNAH) is a powerful tool for identifying noise sources from the partially known sound pressure field.The acoustical property to be reconstructed on the surface of interest is related to the partially measured pressure on the hologram surface in terms of sampling and bandlimiting matrices,which cost more in computation.A one-step procedure based on measuring of the normal component of the particle velocity is described,including the mathematical formulation.The numerical simulation shows that one-step PNAH based on particle velocity can obtain more accurately reconstructed results and it is also less sensitive to noise than the method based on pressure.These findings are confirmed by an underwater near-field acoustical holography experiment conducted with a vector hydrophone array.The experimental results have illustrated the high performance of one-step PNAH based on particle velocity in the reconstruction of sound field and the advantages of a vector hydrophone array in an underwater near-field measurement.展开更多
The phase errors among the components of a single acoustic vector sensor cause the direction-of-arrival(DOA) estimation error of the existing methods.In order to address this issue,a DOA estimation method is proposed,...The phase errors among the components of a single acoustic vector sensor cause the direction-of-arrival(DOA) estimation error of the existing methods.In order to address this issue,a DOA estimation method is proposed,which is robust to the phase errors.The proposed method first utilizes the Hadamard product of the principal eigenvector of the covariance matrix of the received signal by the single vector sensor and its conjugate vector to construct the spatial spectrum in order to estimate the DOA of the underwater target.Since the Hadamard product eliminates the phase errors,this estimation is independent of the phase errors.However,it is ambiguous.Afterwards,the phase-error estimate is explored to eliminate the ambiguity and get the correct DOA estimate.The proposed method performs independently of the phase errors and obtains high accuracy.The simulation results and the experimental result demonstrate the proposed method is robust to the phase errors.Furthermore,in the presence of the phase errors,it performs better than the average acoustic intensity method,the CAPON method,and the MUSIC method,in terms of estimation accuracy.In addition,the simulation results indicate that the estimation accuracy of the proposed method approaches to the Cramer-Rao bound(CRB).展开更多
In the scenario of isotropic ambient noise,the inequality between the noise powers of the pressure and velocity channels of a single acoustic vector sensor causes a virtual source for subspace-based methods,which seri...In the scenario of isotropic ambient noise,the inequality between the noise powers of the pressure and velocity channels of a single acoustic vector sensor causes a virtual source for subspace-based methods,which seriously degrades the performance of the conventional multiple signal classification(MUSIC) method.In order to solve this problem,an increased-rank MUSIC method and a weighted-amplitude MUSIC method are presented.The increased-rank MUSIC method augments the dimension of the signal subspace to eliminate the effect of the virtual source.Among the increased-rank,weighted-amplitude,and conventional MUSIC methods,the increased-rank MUSIC method gains the highest estimation accuracy in the cases of one source.Moreover,its performance approaches to the the Cramer-Rao bound(CRB).However,it fails in the case of two sources.The weighted-amplitude MUSIC method weights the amplitude of the received signal to eliminate the virtual source and it can identify two sources.展开更多
Based on Keller-Miksis model, the influences of multiple control parameters, such as acoustic pressure amplitude, acoustic frequency and bubble radius at rest, on the complicated dynamics characteristics of nonlinear ...Based on Keller-Miksis model, the influences of multiple control parameters, such as acoustic pressure amplitude, acoustic frequency and bubble radius at rest, on the complicated dynamics characteristics of nonlinear bubble oscillation driven by acoustic wave are discussed by utilizing a variety of numerical analysis methods, and the restrictive relationships among different parameters are analyzed. It is shown that chaotic state can occur only in the condition of all of the parameters in the suitable threshold, as the same time, chaotic state is the result of interaction of multiple control parameters. Fhrthermore, the power spectral expansion and energy conversion are existed in this nonlinear system. It is certified that the stronger acoustic pressure amplitude, the greater the sub-harmonic energy, besides, the energy attenuation of fundamental harmonic is also much greater.PACS numbers： 43.25, 43.35, 05.45展开更多
基金supported by the Fundamental Research Funds For the Central Universities (Grant No. HEUCFR1013)
文摘Near-field acoustical holography (NAH) is a powerful tool for identifying noise sources and visualizing acoustic field. By recording the acoustic pressures in the near-field, the acoustic quantities in the whole 3-D field can be reconstructed and predicted. However, the current theory of NAH is not applicable to tracking large scale moving noise sources. Therefore, the hybrid near-field acoustical holography is developed for reconstructing acoustic radiation, which is derived from statistically optimized near-field acoustical holography (SONAH) and moving frame acoustical holography (MFAH). The theoretical formulation is systematically addressed. This method enables us to visualize the noise generated by moving noise sources and the measurement array can be smaller than the source, which improves the practicability and efficiency of this technology. Numerical simulations are presented to demonstrate the advantages of hybrid NAH. Then, two experiments have been carried out with a line array of hydrophones. The results of simulations and experiments support the proposed theory, which shows the advantage of hybrid NAH in the reconstruction of an acoustic field in an underwater holographic measurement.
基金supported by the National Natural Science Foundation of China(Grant No.11204049)the National Defence Research Funds (Grant No.7131107 and 51310040202)the Fundamental Research Funds For the Central Universities(Grant No.HEUCFR1013 and HEUCF120504)
文摘One-step patch near-field acoustical holography(PNAH) is a powerful tool for identifying noise sources from the partially known sound pressure field.The acoustical property to be reconstructed on the surface of interest is related to the partially measured pressure on the hologram surface in terms of sampling and bandlimiting matrices,which cost more in computation.A one-step procedure based on measuring of the normal component of the particle velocity is described,including the mathematical formulation.The numerical simulation shows that one-step PNAH based on particle velocity can obtain more accurately reconstructed results and it is also less sensitive to noise than the method based on pressure.These findings are confirmed by an underwater near-field acoustical holography experiment conducted with a vector hydrophone array.The experimental results have illustrated the high performance of one-step PNAH based on particle velocity in the reconstruction of sound field and the advantages of a vector hydrophone array in an underwater near-field measurement.
基金supported by the National Natural Science Foundation of China (61701133,11674074)the Stable Supporting Fund of Acoustics Science and Technology Laboratory (SSJSWDZC2018003)。
文摘The phase errors among the components of a single acoustic vector sensor cause the direction-of-arrival(DOA) estimation error of the existing methods.In order to address this issue,a DOA estimation method is proposed,which is robust to the phase errors.The proposed method first utilizes the Hadamard product of the principal eigenvector of the covariance matrix of the received signal by the single vector sensor and its conjugate vector to construct the spatial spectrum in order to estimate the DOA of the underwater target.Since the Hadamard product eliminates the phase errors,this estimation is independent of the phase errors.However,it is ambiguous.Afterwards,the phase-error estimate is explored to eliminate the ambiguity and get the correct DOA estimate.The proposed method performs independently of the phase errors and obtains high accuracy.The simulation results and the experimental result demonstrate the proposed method is robust to the phase errors.Furthermore,in the presence of the phase errors,it performs better than the average acoustic intensity method,the CAPON method,and the MUSIC method,in terms of estimation accuracy.In addition,the simulation results indicate that the estimation accuracy of the proposed method approaches to the Cramer-Rao bound(CRB).
基金supported by the National Natural Science Foundation of China(61701133)the Fundamental Research Funds for the Central Universities(HEUCFJ180502,HEUCFM180505)the Stable Supporting Fund of Acoustics Science and Technology Laboratory(SSJSWDZC2018003)
文摘In the scenario of isotropic ambient noise,the inequality between the noise powers of the pressure and velocity channels of a single acoustic vector sensor causes a virtual source for subspace-based methods,which seriously degrades the performance of the conventional multiple signal classification(MUSIC) method.In order to solve this problem,an increased-rank MUSIC method and a weighted-amplitude MUSIC method are presented.The increased-rank MUSIC method augments the dimension of the signal subspace to eliminate the effect of the virtual source.Among the increased-rank,weighted-amplitude,and conventional MUSIC methods,the increased-rank MUSIC method gains the highest estimation accuracy in the cases of one source.Moreover,its performance approaches to the the Cramer-Rao bound(CRB).However,it fails in the case of two sources.The weighted-amplitude MUSIC method weights the amplitude of the received signal to eliminate the virtual source and it can identify two sources.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China(11204050,11204049)
文摘Based on Keller-Miksis model, the influences of multiple control parameters, such as acoustic pressure amplitude, acoustic frequency and bubble radius at rest, on the complicated dynamics characteristics of nonlinear bubble oscillation driven by acoustic wave are discussed by utilizing a variety of numerical analysis methods, and the restrictive relationships among different parameters are analyzed. It is shown that chaotic state can occur only in the condition of all of the parameters in the suitable threshold, as the same time, chaotic state is the result of interaction of multiple control parameters. Fhrthermore, the power spectral expansion and energy conversion are existed in this nonlinear system. It is certified that the stronger acoustic pressure amplitude, the greater the sub-harmonic energy, besides, the energy attenuation of fundamental harmonic is also much greater.PACS numbers： 43.25, 43.35, 05.45
