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    Wyświetlanie 1-3 z 3
    Tytuł:
    Modeling of acoustic field for a parametric focusing source using the spheroidal beam equation
    Autorzy:
    Yu, L.
    Li, J.
    Shi, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/258564.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    parametric focusing source
    difference frequency wave
    SBE
    acoustic field
    Opis:
    A theoretical model of acoustic field for a parametric focusing source on concave spherical surface is proposed. In this model, the source boundary conditions of the Spheroidal Beam Equation (SBE) for difference frequency wave excitation were studied. Propagation curves and beam patterns for difference frequency component of the acoustic field are compared with those obtained for Khokhlov-Zabolotskaya-Kuznetsov (KZK) model. The results demonstrate that the focused parametric model of SBE is good valid for a large aperture angle in the strongly focused acoustic field. It is also investigated that high directivity and good focal ability with the decreasing of downshift ratio and the increasing of half-aperture angle for the focused parametric model of SBE.
    Źródło:
    Polish Maritime Research; 2015, S 1; 43-47
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    High-Directional Sound Propagation Over the Earth’s Surface
    Autorzy:
    Rakov, Denis S.
    Rakov, Aleksandr S.
    Chursin, Yury A.
    Pavlichev, Vsevolod V.
    Igumnov, Artyom O.
    Powiązania:
    https://bibliotekanauki.pl/articles/1953521.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    parametric loudspeaker
    ultrasound
    primary frequency
    difference frequency
    radiation pattern
    outdoor propagation of sound
    sound attenuation
    Opis:
    The article discusses the issues of accounting the direction pattern of parametric antenna array the propagation of sound over the Earth’s surface. As a radiator, a parametric antenna array is used. A description is given of measuring equipment and experimental research methods. The Delaney-Bezley model was used as a model of the Earth’s surface impedance. The research results showed the importance of accounting the direction pattern of parametric antenna array in predicting the sound pressure level of a propagating acoustic signal over the Earth’s surface. On the example of a difference signal with a frequency of 2 kHz, the calculation of the sound pressure level on a 100-meter path with the influence of the Earth’s surface is shown. The results obtained showed a good agreement between the theoretical calculation and experimental data.
    Źródło:
    Archives of Acoustics; 2020, 45, 4; 747-752
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on Chinese Speech Intelligibility Under Different Low-Frequency Characteristics of Reverberation Time Using a Hybrid Method
    Autorzy:
    Huang, Wuqiong
    Peng, Jianxin
    Xie, Tinghui
    Powiązania:
    https://bibliotekanauki.pl/articles/31339871.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    low frequency
    speech intelligibility
    classroom
    finite-difference time-domain method
    Opis:
    Reverberation time (RT) is an important indicator of room acoustics, however, most studies focus on the mid-high frequency RT, and less on the low-frequency RT. In this paper, a hybrid approach based on geometric and wave methods was proposed to build a more accurate and wide frequency-band room acoustic impulse response. This hybrid method utilized the finite-difference time-domain (FDTD) method modeling at low frequencies and the Odeon simulation at mid-high frequencies, which was investigated in a university classroom. The influence of the low-frequency RT on speech intelligibility was explored. For the low-frequency part, different impedance boundary conditions were employed and the effectiveness of the hybrid method has also been verified. From the results of objective acoustical parameters and subjective listening experiments, the smaller the low-frequency RT was, the higher the Chinese speech intelligibility score was. The syllables, consonants, vowels, and the syllable order also had significant effects on the intelligibility score.
    Źródło:
    Archives of Acoustics; 2023, 48, 3; 151-157
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-3 z 3

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