Temat: acoustic velocity - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Obrazowanie wartości skutecznej prędkości akustycznej na bazie pomiarów PIV
Imaging of the effective value of acoustic velocity based on PIV measurements
Autorzy:: Mickiewicz, W.
Jabłoński, M. J.
Powiązania:: https://bibliotekanauki.pl/articles/151736.pdf
Data publikacji:: 2012
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: prędkość akustyczna
obrazowanie
PIV
acoustic velocity
visualisation
Opis:: Laserowa anemometria obrazowa (PIV) służy obrazowaniu pól prędkości i jest stosowana do przepływów masowych, a w ostatnich latach również do pól akustycznych, w których chwilowa prędkość akustyczna w danym punkcie pola jest wielkością wektorową zmienną w czasie. W artykule zaproponowano sposób wizualizacji pola prędkości akustycznej w formie rozkładu odcinków, których długość odpowiada wartości skutecznej prędkości a nachylenie jest związane z kierunkiem przepływu energii akustycznej.
Laser Particle Image Velocimetry is a modern method for visualisation of a velocity field, commonly used in fluid mechanics in order to describe the distribution of mass flows. Recently, this method has been applied to acoustic field visualisation, where the instantaneous particle velocity varies in terms of direction and vector orientation. The paper discusses utility of that approach in comparison to the full sound intensity description.A widely applied parameter describing the energy flow in an acoustic field is the intensity vector (formula (1)). In order to evaluate this parameter, there are needed measurements of the acoustic velocity and pressure to be taken. The evaluation of the parameter needs two basic measurements: acoustic velocity and pressure. In case of the lack of the direct pressure or velocity data, the output is a scalar value. The paper describes the distribution of velocity vectors in several subsequent phases (Fig. 1) and presents a mathematical formula (formula (11)) which provides possibility to obtain the main direction of the acoustic energy propagation. The data obtained from the laser system (Figs. 2 and 3) is compared with the hot-wire anemometry (Fig. 4 left) and the sound intensity distribution (Fig. 4 right).
Źródło:: Pomiary Automatyka Kontrola; 2012, R. 58, nr 11, 11; 930-933
0032-4140
Pojawia się w:: Pomiary Automatyka Kontrola
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 2.

Tytuł:: Technique for Measuring Spatial Distribution of the Surface Acoustic Wave Velocity in Metals
Autorzy:: Mokryy, O.
Tsyrulnyk, O.
Powiązania:: https://bibliotekanauki.pl/articles/177231.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: ultrasound
surface acoustic waves
acoustic wave velocity
spatial resolution
Opis:: In this paper a possibility of determining a local velocity of the surface acoustic Rayleigh waves using a transducer, with the rigidly connected emitting and receiving parts, is considered. A problem on spatial resolution of such a transducer for investigation of inhomogeneous specimens is also examined. A high spatial resolution can be obtained due to the transducer displacement by a value less than the distance between the emitting and receiving parts. It is shown that in this case it is not necessary to measure the transducer displacement with a high accuracy for precise determination of the velocity. Such an effect is obtained through measuring the velocity of surface waves in one local region of the specimen with respect to the other. The criterion for optimal spatial resolution selection during spatially inhomogeneous specimens study is also proposed. The proposed criterion use is illustrated on the example of the determination of spatial distribution of the surface acoustic velocity in a steel specimen subjected to inhomogeneous plastic deformation.
Źródło:: Archives of Acoustics; 2016, 41, 4; 741-746
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 3.

Tytuł:: Systematic error of acoustic particle image velocimetry and its correction
Autorzy:: Mickiewicz, W.
Powiązania:: https://bibliotekanauki.pl/articles/221013.pdf
Data publikacji:: 2014
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: particle image velocimetry
acoustic measurement
acoustic particle velocity
sound field analysis
Opis:: Particle Image Velocimetry is getting more and more often the method of choice not only for visualization of turbulent mass flows in fluid mechanics, but also in linear and non-linear acoustics for non-intrusive visualization of acoustic particle velocity. Particle Image Velocimetry with low sampling rate (about 15Hz) can be applied to visualize the acoustic field using the acquisition synchronized to the excitation signal. Such phase-locked PIV technique is described and used in experiments presented in the paper. The main goal of research was to propose a model of PIV systematic error due to non-zero time interval between acquisitions of two images of the examined sound field seeded with tracer particles, what affects the measurement of complex acoustic signals. Usefulness of the presented model is confirmed experimentally. The correction procedure, based on the proposed model, applied to measurement data increases the accuracy of acoustic particle velocity field visualization and creates new possibilities in observation of sound fields excited with multi-tonal or band-limited noise signals.
Źródło:: Metrology and Measurement Systems; 2014, 21, 3; 447-460
0860-8229
Pojawia się w:: Metrology and Measurement Systems
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 4.

Tytuł:: Studies of densities, viscosities and ultrasonic speeds of binary mixtures containing isopropyl alcohol and ketones at different temperatures
Autorzy:: Srinivas, S. S. J.
Tulasi Koteswari Bai, B.
Babu Rao, K.
Narendra, K.
Sarath Babu, M.
Powiązania:: https://bibliotekanauki.pl/articles/412144.pdf
Data publikacji:: 2013
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:: ultrasonic velocity
density
viscosity
acoustic parameters
Opis:: The densities, viscosities and ultrasonic velocities of binary liquid mixtures of Isopropyl alcohol with acetophenone and methyl isobutyl ketone (MIBK) have been measured at temperatures 298.15 and 308.15 K over the entire range of mole fraction. From these data, acoustical parameters such as adiabatic compressibility (β), free volume (Vf) and free length (Lf) have been estimated using the standard relations. The results are interpreted in terms of molecular interactions present in the mixtures.
Źródło:: International Letters of Chemistry, Physics and Astronomy; 2013, 10, 2; 151-158
2299-3843
Pojawia się w:: International Letters of Chemistry, Physics and Astronomy
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 5.

Tytuł:: Velocity Field Characteristics at the Inlet to a Pipe Culvert
Autorzy:: Kolerski, T.
Wielgat, P.
Powiązania:: https://bibliotekanauki.pl/articles/241162.pdf
Data publikacji:: 2014
Wydawca:: Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:: Culvert
Acoustic Doppler Velocitymeter
velocity field
turbulence
Opis:: A poorly designed culvert inlet structure causes scouring, which can lead to the collapse of the culvert and significant damage to the neighboring land. A set of laboratory tests was evaluated to examine velocity distribution at the culvert inlet. A three-dimensional acoustic Doppler velocimeter was used to measure instantaneous flow velocity upstream of the culvert. The analysis of mean velocities, turbulence strength, and Reynolds stresses was performed to understand the flow structure near the culvert entrance.
Źródło:: Archives of Hydro-Engineering and Environmental Mechanics; 2014, 61, 3-4; 127--140
1231-3726
Pojawia się w:: Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 6.

Tytuł:: New Surface-Plasmon-Polariton-Like Acoustic Surface Waves at the Interface Between Two Semi-Infinite Media
Autorzy:: Kiełczyński, Piotr
Powiązania:: https://bibliotekanauki.pl/articles/31340115.pdf
Data publikacji:: 2022
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:: shear horizontal acoustic waves
surface plasmon polaritons
phase velocity
group velocity
Poynting vector
Opis:: This paper presents theory of new shear horizontal (SH) acoustic surface waves that propagate along the interface of two semi-infinite elastic half-spaces, one of which is a conventional elastic medium and a second one an elastic metamaterial with a negative and frequency dependent shear elastic compliance. This new surface waves have only one transverse component of mechanical displacement, which has a maximum at the interface and decays exponentially with distance from the interface. Similar features are also shown by the acoustic shear horizontal Maerfeld-Tournois surface waves propagating at the interface of two semi-infinite elastic media due to the piezoelectric effect that should occur in at least one semi-space. The proposed new shear horizontal acoustic surface waves exhibit also strong formal similarities with the electromagnetic surface waves of the surface plasmon polariton (SPP) type, propagating along a metal-dielectric planar interface. In fact, the new shear horizontal elastic surface waves possess a large number of properties that are inherent for the SPP electromagnetic surface waves, such as strong subwavelength concentration of the wave field in the proximity of the guiding interface, low phase and group velocity etc. As a result, the new shear horizontal acoustic surface waves can find applications in sensors with extremely high sensitivity, employed in measurements of various physical parameters, such as viscosity of liquids, as well as in biosensors, chemosensors, or a near field acoustic microscopy (subwavelength imaging) and miniaturized devices of microwave acoustics.
Źródło:: Archives of Acoustics; 2022, 47, 3; 363-371
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 7.

Tytuł:: Microphone Based Acoustic Vector Sensor for Direction Finding with Bias Removal
Autorzy:: Wajid, Mohd
Kumar, Arun
Bahl, Rajendar
Powiązania:: https://bibliotekanauki.pl/articles/2141636.pdf
Data publikacji:: 2022
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: acoustic measurements
acoustic sensor
acoustic vector sensor
direction-of-arrival estimation
finite element analysis
microphones
particle velocity
sound source localization
Opis:: The acoustic vector sensor (AVS) is used to measure the acoustic intensity, which gives the direction-of-arrival (DOA) of an acoustic source. However, while estimating the DOA from the measured acoustic intensity the finite microphone separation (d) in a practical AVS causes angular bias. Also, in the presence of noise there exists a trade off between the bias (strictly increasing function of d) and variance (strictly decreasing function of d) of the DOA estimate. In this paper, we propose a novel method for mitigating the angular bias caused due to finite microphone separation in an AVS. We have reduced the variance by increasing the microphone separation and then removed the bias with the proposed bias model. Our approach employs the finite element method (FEM) and curves fitting to model the angular bias in terms of microphone separations and frequency of a narrowband signal. Further, the bias correction algorithm based on the intensity spectrum has been proposed to improve the DOA estimation accuracy of a broadband signal. Simulation results demonstrate that the proposed bias correction scheme significantly reduces the angular bias and improves the root mean square angular error (RMSAE) in the presence of noise. Experiments have been performed in an acoustic full anechoic room to corroborate the effect of microphone separation on DOA estimation and the efficacy of the bias correction method.
Źródło:: Archives of Acoustics; 2022, 47, 2; 151-167
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 8.

Tytuł:: An Integrated Approach of Profi le Studies for Surface Water Velocity on a Steep Slope in a Rectangular Channel
Autorzy:: Ayalew, Abebe Temesgen
Koshuma, Abera Ermias
Ayele, Mesfi n Amaru
Dirate, Democracy Dilla
Powiązania:: https://bibliotekanauki.pl/articles/2181750.pdf
Data publikacji:: 2022
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: fluid mechanics
velocity profiles
rectangular channel
Pitot tube
Acoustic Doppler Velocitymeter
ADV
Opis:: The flow velocity of water and its accurate surface profile estimation is important parameter as changes in climate increases the uneven rainfall patterns causing flood in downstream. It is important to know the velocity profile in steep open channel flows for solving the soil erosion, flooding and sediment transport problems in rivers or streams on steep slopes. A fixed bed laboratory experiment for a rectangular channel with steep slope is conducted to find the velocity profiles and surface profiles at different sections. Velocity profiles are presented at different sections in rectangular channel with steep slope. The outcome of the laboratory based experimental investigation shows that the velocity and surface profiles are influenced by the depth of flow of water and channel bed slope respectively.
Źródło:: Advances in Science and Technology. Research Journal; 2022, 16, 2; 74--80
2299-8624
Pojawia się w:: Advances in Science and Technology. Research Journal
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 9.

Tytuł:: Identification of Miocene gas deposits from seismic data in the southeastern part of the Carpathian Foredeep
Autorzy:: Pietsch, K.
Jarzyna, J.
Powiązania:: https://bibliotekanauki.pl/articles/2059893.pdf
Data publikacji:: 2002
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: Carpathian Foredeep
seismics
seismostratigraphy
velocity model
acoustic full wavetrain
attenuation of seismic waves
Opis:: Seismic interpretations are normally made to help identify and locate structural and stratigraphic traps for oil. We focus on problems in interpreting seismic sections in sandy-shaly Miocene deposits which occur in the eastern part of the Polish Carpathian Foredeep. There, the structural picture yielded by the seismic section is not in good agreement with the known structure and a correct interpretation of the seismic wave field, based on seismic modelling, is needed to ensure proper location of exploratory and production wells. We show that the correct choice of petrophysical parameters in these deposits allows interpretation of the seismic image in terms of a multi-horizon gas body. A decrease in velocity, characteristic of gas-saturated beds, was not observed in velocity obtained from sonic measurements. Therefore, several versions of a seismogeological model were constructed based on the results of integrated log interpretation. A model using seismic wave velocity obtained from acoustic wave velocity and a quality factor Q, as a measure of attenuation of elastic waves, was of particular significance. In addition to the petrophysical parameters, the strata geometry necessary to construct a seismogeological model, was determined. Combining the interpreted geometry and information regarding depths of lithostratigraphic units an anticlinal structure was deduced in the gas-rich zone. A comparison of synthetic seismograms calculated using only sonic velocity and seismic velocity corrected for attenuation, with the recorded seismic traces, shows that the best agreement was obtained for a model which included the attenuation. Differences observed between the synthetic and field sections were a basis for determining local direct hydrocarbon indicators, which were then used to identify hydrocarbon deposits in the recorded seismic section.
Źródło:: Geological Quarterly; 2002, 46, 4; 449-462
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 10.

Tytuł:: Określanie prędkości fal poprzecznych (VS) na podstawie danych geofizyki otworowej
Shear wave velocity (VS) determinations on the basis of well log data
Autorzy:: Bała, M.
Powiązania:: https://bibliotekanauki.pl/articles/2074671.pdf
Data publikacji:: 2009
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: prędkość kompresyjnej fali
określanie prędkości fal
akustyczne ciągi falowe
otwory
porowatość
gęstość
velocity of compressional waves
velocity of shear waves
acoustic wavetrains
elastic module
porosity
bulk density
Opis:: The knowledge of elastic parameters, especially of P-wave and S-wave velocities as a function of depth, is important for interpretation of seismic waves and well log data. Information on velocities of P and S waves is obtained from quantitative interpretation of acoustic full waveforms recorded in a borehole in addition to standard PA measurements. When acoustic full-waveform data are not acquired in boreholes, one of methods for calculating P-wave and S-wave velocities is their estimation with the use of theoretical models of porous media. This requires introduction of several lithological and reservoir parameters of rocks that are obtained from interpretation of well log data. Other methods of S-wave velocity calculation is based on statistical relationships between velocities of both types of waves obtained on the basis of laboratory studies. In this paper, the theoretical Biot-Gassmann's and the Kuster-Toksöz's models are briefly described and results of calculations of P-wave and S-wave velocities are given. The empirical relationships between VP and VS, which are applied in many computer programs used by major geophysical companies, were also analysed.
Źródło:: Przegląd Geologiczny; 2009, 57, 12; 1057-1066
0033-2151
Pojawia się w:: Przegląd Geologiczny
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Informacja

Wyszukujesz frazę "acoustic velocity" wg kryterium: Temat

Źródło danych

Dostawca treści

Kolekcja

Rok wydania

Wydawca

Temat

Autor

Typ dokumentu

Język