Space-time acoustic holography of moving inhomogeneities

Matveev, A. L.; Mityugov, V. V.; Потапов, А. И.

doi:10.1134/1.1355805

Cited by 6 publications

(6 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…L'ordre de grandeur des vitesses propagées est de 200 à 300 m/s [3], ce qui indique que la fréquence de coupure, au delà de laquelle les modes acoustiques sont évanescents, se situe vers 300 kHz pour des billes de verre de diamètre 0,2 mm [3,2,4,5]. En raison de l'atténuation croissante avec la fréquence, seule l'onde BF associée à la modulation d'amplitude du paquet d'onde (sous forme d'un profil gaussien) pourra se propager dans le matériau granulaire, comme cela a pu être observé par divers auteurs [3,[6][7][8], et expliqué théoriquement [1,8,9]. La Fig.…”

Section: Et Al C R Mecanique 331 (2003)unclassified

Self-demodulation acoustic signatures for nonlinear propagation in glass beads

Tournat

Castagnède

Gusev

et al. 2003

Comptes Rendus. Mécanique

View full text Add to dashboard Cite

The present Note describes some experimental work related to the nonlinear propagation of acoustic waves in granular media such as unconsolidated glass beads. The studied nonlinear effect is a self-demodulation process performed with the operation of the so-called parametric transmitting antenna. The pump (or carrier) wave is generated by a high power ultrasonic broad-band transducer (100 kHz central frequency) which is LF (low frequency, i.e., a few kHz) amplitude modulated. As the attenuation of acoustic waves increases with frequency, only the LF demodulated wave can be transmitted. A parametric study is performed where the HF central frequency is monitored between 60 and 300 kHz. The LF demodulation profile versus the HF frequency is modified, its shape being temporally derived almost twice. A numerical analysis of the order of temporal derivation is done in the Fourier domain, its value varying from 1.25 to 2.7. Qualitative agreement with current theoretical models is described, and an advanced theoretical analysis by the same authors [Phys. Rev. E 66 (2002) 041303], taking into account absorption, nonlinearity, dispersion and scattering, is briefly discussed.

show abstract

Section: Et Al C R Mecanique 331 (2003)unclassified

Self-demodulation acoustic signatures for nonlinear propagation in glass beads

Tournat

Castagnède

Gusev

et al. 2003

Comptes Rendus. Mécanique

View full text Add to dashboard Cite

show abstract

“…The resulting signal then has the form (18) where and are the useful signal amplitude and phase, respectively, for a hydrophone located at depth . Recall that the phase cannot be assumed known and, therefore, must be eliminated through the absolute value calculation in (16).…”

Section: Partially Coherent Accumulation With Coherent Signalmentioning

confidence: 99%

“…Suppressing the frequency index but making explicit the dependence on , define (16) where is the matched filter output (9) for hydrophone and is the total number of hydrophones in the array. The first group includes the channels with numbers from 1 to , while the second group includes the channels with numbers from 2 to , etc.…”

Section: Partially Coherent Accumulation With Coherent Signalmentioning

confidence: 99%

See 1 more Smart Citation

Forward Scattering Observation With Partially Coherent Spatial Processing of Vertical Array Signals in Shallow Water

Matveev

Spindel

Rouseff

2007

IEEE J. Oceanic Eng.

View full text Add to dashboard Cite

In this paper, we address the problem of detecting an inhomogeneity in shallow water by observing changes in the acoustic field as the inhomogeneity passes between an acoustic source and vertical line array of receivers. A signal processing scheme is developed to detect the perturbed field in the presence of the much stronger primary source signal, and to estimate such parameters as the time when the inhomogeneity crosses the source-receiver path, its velocity, and its size. The effectiveness of incoherent, coherent, and partially coherent spatial processing of the array signals is evaluated using models and data obtained from experiments in a lake. The effect of different bottom types is also considered, and it is shown that partially coherent processing can have a significant advantage depending on the bottom type. Estimates of the minimum input signal-to-noise ratios (SNRs) for which the diffracted signal can be observed are presented.

show abstract

“…Different aspects of this problem, as well as the related problem of low-angle acoustic observation, were studied in [8][9][10][11][12][13][14]. For relatively small observation distances, it is reasonable to use high-frequency (HF) hydroacoustic fields [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Tomographic observation of shallow-water inhomogeneities in the case of probing by a focused high-frequency acoustic field. I. Structure of simulation model

Smirnov

Khil’ko

2009

Radiophys Quantum El

View full text Add to dashboard Cite

UDC 534.26We study the possibilities of acoustic tomography observation of small-size bodies in shallow-water layered oceanic waveguides within the framework of geometric acoustics. For increasing the spatial resolution and sensitivity in the considered inverse problem, we used the waveguide-matched focusing of the received and radiated fields into the region of expected location of the observed body. The algorithm of observation in this case consists of search for a global extremum of decision statistics, which is determined by the difference between the measured data and the hypothetic body location. Such hypotheses are formed on the basis of a priori information in the form of the waveguide model and the data on the structure of the observation system. For decreasing the influence of noise associated with the interference of fields in the waveguide, selection of separate tomographic ray projections with the subsequent incoherent accumulation of partial images is used. A tomographic shallow-water observation model based on such principles is analyzed.

show abstract

Space-time acoustic holography of moving inhomogeneities

Cited by 6 publications

References 4 publications

Self-demodulation acoustic signatures for nonlinear propagation in glass beads

Self-demodulation acoustic signatures for nonlinear propagation in glass beads

Forward Scattering Observation With Partially Coherent Spatial Processing of Vertical Array Signals in Shallow Water

Tomographic observation of shallow-water inhomogeneities in the case of probing by a focused high-frequency acoustic field. I. Structure of simulation model

Contact Info

Product

Resources

About