By reduction to one dimensional, periodic as well as rotating pulse heat sources, investigation on heat transfer characteristics with rotating body is carried out. Similar to the fluid flow, a new set of dimensionless...By reduction to one dimensional, periodic as well as rotating pulse heat sources, investigation on heat transfer characteristics with rotating body is carried out. Similar to the fluid flow, a new set of dimensionless numbers, namely quasi-Peclet numbers Pe 1, Pe 2 and Biot number Bi composed of angular velocity ω , thermophysical parameter, and geometry size are proposed, and applied to the dimensionless equations. Simulation result shows that it plays a decisive role in the process of the heat transfer. However, more important is that the numerical simulation depicts the difference between microcosmic and macroscopic structures of the temperature distribution, and reveals the influence of the relative relation of the dimensionless criterion numbers upon heat transfer characteristics.展开更多
Mode composition beamforming(MCB)is a frequency-domain rotating beamforming method for rotating acoustic source localization.Compared with other rotating beamforming methods,MCB has both wide applicability and high co...Mode composition beamforming(MCB)is a frequency-domain rotating beamforming method for rotating acoustic source localization.Compared with other rotating beamforming methods,MCB has both wide applicability and high computational efficiency.The expression forMCB in literature is however not suitable for the application of deconvolution algorithms,which limits further improvements of dynamic range and spatial resolution ofMCB.In this work,application of deconvolution algorithms to MCB is investigated.Firstly,the expression of MCB is transformed into a matrix form.Then the deconvolution algorithms of MCB,including DAMAS and CLEAN-SC,are derived based on the matrix form of MCB.Nextly the deconvolution algorithms of MCB are verified through a benchmark simulation case.Lastly deconvolution algorithms of MCB are applied in a phased array measurement for the rotor of an unmanned aerial vehicle to improve the dynamic range and spatial resolution of rotating source localization.展开更多
The time-domain inverse technique based on the time-domain rotating equivalent source method has been proposed to localize and quantify rotating sound sources. However, this technique encounters two problems to be add...The time-domain inverse technique based on the time-domain rotating equivalent source method has been proposed to localize and quantify rotating sound sources. However, this technique encounters two problems to be addressed: one is the time-consuming process of solving the transcendental equation at each time step, and the other is the difculty of controlling the instability problem due to the time-varying transfer matrix. In view of that, an improved technique is proposed in this paper to resolve these two problems. In the improved technique, a de-Dopplerization method in the time-domain rotating reference frame is frst applied to eliminate the Doppler efect caused by the source rotation in the measured pressure signals, and then the restored pressure signals without the Doppler efect are used as the inputs of the time-domain stationary equivalent source method to locate and quantify sound sources. Compared with the original technique, the improved technique can avoid solving the transcendental equation at each time step, and facilitate the treatment of the instability problem because the transfer matrix does not change with time. Numerical simulation and experimental results show that the improved technique can eliminate the Doppler efect efectively, and then localize and quantify the rotating nonstationary or broadband sources accurately. The results also demonstrate that the improved technique can guarantee a more stable reconstruction and compute more efciently than the original one.展开更多
In the actual application of microphone array for sound source localization,it is inevitable that the installation position of array is not accurate,which will affect the localization performance.Virtual rotating arra...In the actual application of microphone array for sound source localization,it is inevitable that the installation position of array is not accurate,which will affect the localization performance.Virtual rotating array(VRA)beamforming is a rotating sound source localization algorithm in frequency domain.The basic concept is to make the sound source and the microphones in a relatively static state,so the center of the microphone array and rotating sound source must be strictly on the same axis.This paper is to study the influence on the performance of VRA rotating sound source localization when the microphone array is not coaxial with the rotating sound source.VRA with ring array and H0V5 array are used in this study to simulate the influence of various degrees of deviation in the x direction on the localization performance of different frequencies and rotational speeds.The results show that VRA with ring array is more stable and less affected by the rotational speed in the case of installation deviation that make the array non-coaxial with the rotating source.As the frequency increases,the requirement for coaxial becomes more stringent,regardless of the array configuration and rotational speed.In addition,VRA with ring array can observe the distance of deviation from the CLEAN-SC source maps at higher frequencies of 5 kHz and 8 kHz.Results of this research can provide reference and guidance for the coaxial restriction of VRA in practical engineering applications.展开更多
Virtual rotating array(VRA)beamforming is a robust technique in the identification of rotating sound sources in frequencydomain.Under normal circumstances,the configuration of microphone array is established in ring g...Virtual rotating array(VRA)beamforming is a robust technique in the identification of rotating sound sources in frequencydomain.Under normal circumstances,the configuration of microphone array is established in ring geometry centred around the rotating axis.Two interpolation methods for arbitrary microphone configurations are proposed by Jekosch and Sarradj(Acoustics,2020).One is to construct a mesh between all stationary microphones using Delaunay-triangulation,another one is a meshless technique based on radial basis function.However,whether other spatial interpolation methods are available in VRA beamforming with arbitrary microphone configurations is still unclear.This paper adds several new spatial interpolation methods in VRA beamforming and detailedly compares the performances of these interpolation methods in simulations.The simulating results demonstrated that all these interpolation methods are successfully applied in VRA beamforming with arbitrary microphone configurations.Inverse distance weighting interpolation method owns the best performance in rotating sound source localization.In addition,all these interpolation methods have poor spectrum construction capability and sound source strength precision.展开更多
文摘By reduction to one dimensional, periodic as well as rotating pulse heat sources, investigation on heat transfer characteristics with rotating body is carried out. Similar to the fluid flow, a new set of dimensionless numbers, namely quasi-Peclet numbers Pe 1, Pe 2 and Biot number Bi composed of angular velocity ω , thermophysical parameter, and geometry size are proposed, and applied to the dimensionless equations. Simulation result shows that it plays a decisive role in the process of the heat transfer. However, more important is that the numerical simulation depicts the difference between microcosmic and macroscopic structures of the temperature distribution, and reveals the influence of the relative relation of the dimensionless criterion numbers upon heat transfer characteristics.
基金supported by the National Science and Technology Major Project of China(2017-II-003-0015).
文摘Mode composition beamforming(MCB)is a frequency-domain rotating beamforming method for rotating acoustic source localization.Compared with other rotating beamforming methods,MCB has both wide applicability and high computational efficiency.The expression forMCB in literature is however not suitable for the application of deconvolution algorithms,which limits further improvements of dynamic range and spatial resolution ofMCB.In this work,application of deconvolution algorithms to MCB is investigated.Firstly,the expression of MCB is transformed into a matrix form.Then the deconvolution algorithms of MCB,including DAMAS and CLEAN-SC,are derived based on the matrix form of MCB.Nextly the deconvolution algorithms of MCB are verified through a benchmark simulation case.Lastly deconvolution algorithms of MCB are applied in a phased array measurement for the rotor of an unmanned aerial vehicle to improve the dynamic range and spatial resolution of rotating source localization.
基金Supported by National Natural Science Foundation of China(Grant Nos.51875147,12174082,51675149)。
文摘The time-domain inverse technique based on the time-domain rotating equivalent source method has been proposed to localize and quantify rotating sound sources. However, this technique encounters two problems to be addressed: one is the time-consuming process of solving the transcendental equation at each time step, and the other is the difculty of controlling the instability problem due to the time-varying transfer matrix. In view of that, an improved technique is proposed in this paper to resolve these two problems. In the improved technique, a de-Dopplerization method in the time-domain rotating reference frame is frst applied to eliminate the Doppler efect caused by the source rotation in the measured pressure signals, and then the restored pressure signals without the Doppler efect are used as the inputs of the time-domain stationary equivalent source method to locate and quantify sound sources. Compared with the original technique, the improved technique can avoid solving the transcendental equation at each time step, and facilitate the treatment of the instability problem because the transfer matrix does not change with time. Numerical simulation and experimental results show that the improved technique can eliminate the Doppler efect efectively, and then localize and quantify the rotating nonstationary or broadband sources accurately. The results also demonstrate that the improved technique can guarantee a more stable reconstruction and compute more efciently than the original one.
基金funded by the National Science and Technology Major Project of China(Y2019-I-0002–0003).
文摘In the actual application of microphone array for sound source localization,it is inevitable that the installation position of array is not accurate,which will affect the localization performance.Virtual rotating array(VRA)beamforming is a rotating sound source localization algorithm in frequency domain.The basic concept is to make the sound source and the microphones in a relatively static state,so the center of the microphone array and rotating sound source must be strictly on the same axis.This paper is to study the influence on the performance of VRA rotating sound source localization when the microphone array is not coaxial with the rotating sound source.VRA with ring array and H0V5 array are used in this study to simulate the influence of various degrees of deviation in the x direction on the localization performance of different frequencies and rotational speeds.The results show that VRA with ring array is more stable and less affected by the rotational speed in the case of installation deviation that make the array non-coaxial with the rotating source.As the frequency increases,the requirement for coaxial becomes more stringent,regardless of the array configuration and rotational speed.In addition,VRA with ring array can observe the distance of deviation from the CLEAN-SC source maps at higher frequencies of 5 kHz and 8 kHz.Results of this research can provide reference and guidance for the coaxial restriction of VRA in practical engineering applications.
基金funded by National Science and Technology Major Project of China(2017-II-003-0015).
文摘Virtual rotating array(VRA)beamforming is a robust technique in the identification of rotating sound sources in frequencydomain.Under normal circumstances,the configuration of microphone array is established in ring geometry centred around the rotating axis.Two interpolation methods for arbitrary microphone configurations are proposed by Jekosch and Sarradj(Acoustics,2020).One is to construct a mesh between all stationary microphones using Delaunay-triangulation,another one is a meshless technique based on radial basis function.However,whether other spatial interpolation methods are available in VRA beamforming with arbitrary microphone configurations is still unclear.This paper adds several new spatial interpolation methods in VRA beamforming and detailedly compares the performances of these interpolation methods in simulations.The simulating results demonstrated that all these interpolation methods are successfully applied in VRA beamforming with arbitrary microphone configurations.Inverse distance weighting interpolation method owns the best performance in rotating sound source localization.In addition,all these interpolation methods have poor spectrum construction capability and sound source strength precision.
