The Experts below are selected from a list of 23181 Experts worldwide ranked by ideXlab platform
Weikang Jiang - One of the best experts on this subject based on the ideXlab platform.
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a hybrid deconvolution approach to separate static and moving single tone acoustic Sources by phased microphone array measurements
2017Co-Authors: Weikang JiangAbstract:Abstract Beamforming approaches are developed to locate and quantify either static or moving acoustic Sources by phased microphone array measurements. They would meet difficulties in mapping combined Sources consisting of both static and moving Sources. In this work, a hybrid deconvolution approach is proposed to separate static and moving single-tone Sources. The approach is derived based on the Source Independence assumption as in the Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS). The static beamforming and the moving beamforming are integrated to construct a linear matrix equation. The Source distributions for the static Sources and moving Sources are simultaneously obtained by solving the equation. Numerical simulations and experiments were implemented on the combined Sources with one static Source and one rotating Source. From the results, the hybrid deconvolution approach shows its effectiveness in separating the two Sources, even with large Source strength differences.
T K Bhattacharya - One of the best experts on this subject based on the ideXlab platform.
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Source Independence of force ripple in linear induction machines
2020Co-Authors: Angshudeep Majumdar, T K BhattacharyaAbstract:In this article, it is shown that in a linear induction machine (LIM), the force ripple that arises due to the magnetic asymmetry does not depend on whether the LIM is being fed from a voltage Source or a current Source. When the LIM is fed from a three-phase balanced voltage Source, the primary voltage is balanced but the LIM draws an unbalanced current from the supply. When the LIM is fed from a three-phase balanced current Source, the primary current is balanced but an unbalanced voltage appears across the LIM terminals. In both these cases, the unbalance creates a ripple in the propulsive force of the LIM. This force ripple increases with the increase in the speed of the LIM. This article shows that at any given speed, the percentage of the ripple component in the propulsive force remains constant irrespective of all operating conditions. The variation of the force ripple with the speed can be represented by a curve, which is unique for one LIM. This curve neither depends on the value of the primary voltage or primary current, nor does it depend on the nature of the energy Source from which the LIM is being supplied. The force ripple arises from the flux distortion due to end effects and can, therefore, be instrumental in estimating the amount of end effects existing in an LIM.
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simulation of a 5 pole linear induction machine using finite element method showing the Source Independence of the peak to peak thrust ripple
2018Co-Authors: Angshudeep Majumdar, T K BhattacharyaAbstract:In this paper, it has been shown that in a Linear Induction Machine (LIM), the thrust ripple that arises due to the magnetic asymmetry, does not depend on whether the machine is being fed from a current Source or a voltage Source. When a LIM is supplied from a balanced 3-phase voltage Source, the LIM draws unbalanced currents from the supply due to the open magnetic circuit of the machine. This unbalance causes a ripple in the developed thrust. The thrust ripple increases with increase in speed of the LIM. However, when the LIM is being fed from a 3-phase balanced current Source, there will be no unbalance in the line currents. This paper shows that even in such a scenario, there is no change in the amount of ripple in the developed thrust at any given speed. The thrust ripple is independent of how much current the LIM draws from the supply, how much terminal voltage is applied or the nature of the Source from which the LIM is being supplied. This means that thrust ripple of a LIM is unique, and its variation depends only on the speed of the machine.
Angshudeep Majumdar - One of the best experts on this subject based on the ideXlab platform.
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Source Independence of force ripple in linear induction machines
2020Co-Authors: Angshudeep Majumdar, T K BhattacharyaAbstract:In this article, it is shown that in a linear induction machine (LIM), the force ripple that arises due to the magnetic asymmetry does not depend on whether the LIM is being fed from a voltage Source or a current Source. When the LIM is fed from a three-phase balanced voltage Source, the primary voltage is balanced but the LIM draws an unbalanced current from the supply. When the LIM is fed from a three-phase balanced current Source, the primary current is balanced but an unbalanced voltage appears across the LIM terminals. In both these cases, the unbalance creates a ripple in the propulsive force of the LIM. This force ripple increases with the increase in the speed of the LIM. This article shows that at any given speed, the percentage of the ripple component in the propulsive force remains constant irrespective of all operating conditions. The variation of the force ripple with the speed can be represented by a curve, which is unique for one LIM. This curve neither depends on the value of the primary voltage or primary current, nor does it depend on the nature of the energy Source from which the LIM is being supplied. The force ripple arises from the flux distortion due to end effects and can, therefore, be instrumental in estimating the amount of end effects existing in an LIM.
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simulation of a 5 pole linear induction machine using finite element method showing the Source Independence of the peak to peak thrust ripple
2018Co-Authors: Angshudeep Majumdar, T K BhattacharyaAbstract:In this paper, it has been shown that in a Linear Induction Machine (LIM), the thrust ripple that arises due to the magnetic asymmetry, does not depend on whether the machine is being fed from a current Source or a voltage Source. When a LIM is supplied from a balanced 3-phase voltage Source, the LIM draws unbalanced currents from the supply due to the open magnetic circuit of the machine. This unbalance causes a ripple in the developed thrust. The thrust ripple increases with increase in speed of the LIM. However, when the LIM is being fed from a 3-phase balanced current Source, there will be no unbalance in the line currents. This paper shows that even in such a scenario, there is no change in the amount of ripple in the developed thrust at any given speed. The thrust ripple is independent of how much current the LIM draws from the supply, how much terminal voltage is applied or the nature of the Source from which the LIM is being supplied. This means that thrust ripple of a LIM is unique, and its variation depends only on the speed of the machine.
William M Humphreys - One of the best experts on this subject based on the ideXlab platform.
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a deconvolution approach for the mapping of acoustic Sources damas determined from phased microphone arrays
2006Co-Authors: Thomas F Brooks, William M HumphreysAbstract:Current processing of acoustic array data is burdened with considerable uncertainty. This study reports an original methodology that serves to demystify array results, reduce misinterpretation, and accurately quantify position and strength of acoustic Sources. Traditional array results represent noise Sources that are convolved with array beamform response functions, which depend on array geometry, size (with respect to Source position and distributions), and frequency. The Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS) method removes beamforming characteristics from output presentations. A unique linear system of equations accounts for reciprocal influence at different locations over the array survey region. It makes no assumption beyond the traditional processing assumption of statistically independent noise Sources. A new robust iterative method seamlessly introduces a positivity constraint (due to Source Independence) that makes the equation system sufficiently deterministic. DAMAS is quantitatively validated using archival data from a variety of prior high-lift airframe component noise studies, including flap edge/cove, trailing edge, leading edge, slat, and calibration Sources. Presentations are explicit and straightforward, as the noise radiated from a region of interest is determined by simply summing the mean-squared values over that region. DAMAS can fully replace existing array processing and presentations methodology in most applications. It appears to dramatically increase the value of arrays to the field of experimental acoustics.
Thomas F Brooks - One of the best experts on this subject based on the ideXlab platform.
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a deconvolution approach for the mapping of acoustic Sources damas determined from phased microphone arrays
2006Co-Authors: Thomas F Brooks, William M HumphreysAbstract:Current processing of acoustic array data is burdened with considerable uncertainty. This study reports an original methodology that serves to demystify array results, reduce misinterpretation, and accurately quantify position and strength of acoustic Sources. Traditional array results represent noise Sources that are convolved with array beamform response functions, which depend on array geometry, size (with respect to Source position and distributions), and frequency. The Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS) method removes beamforming characteristics from output presentations. A unique linear system of equations accounts for reciprocal influence at different locations over the array survey region. It makes no assumption beyond the traditional processing assumption of statistically independent noise Sources. A new robust iterative method seamlessly introduces a positivity constraint (due to Source Independence) that makes the equation system sufficiently deterministic. DAMAS is quantitatively validated using archival data from a variety of prior high-lift airframe component noise studies, including flap edge/cove, trailing edge, leading edge, slat, and calibration Sources. Presentations are explicit and straightforward, as the noise radiated from a region of interest is determined by simply summing the mean-squared values over that region. DAMAS can fully replace existing array processing and presentations methodology in most applications. It appears to dramatically increase the value of arrays to the field of experimental acoustics.
