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Wyszukujesz frazę "cavity noise" wg kryterium: Temat

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    Wyświetlanie 1-5 z 5
    Tytuł:
    Impact of cavity edges shape on aerodynamic noise
    Autorzy:
    Łojek, Paweł
    Czajka, Ireneusz
    Powiązania:
    https://bibliotekanauki.pl/articles/24202002.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    aeroacoustics
    fluid-acoustic coupling
    cavity noise
    aeroakustyka
    hałas generowany przez komorę
    Opis:
    In this article, the analysis of influence of cavity edge shapes on flow-generated noise is performed. The acoustic wave propagation in the channel, that result from the flow, was analyzed. Shape of upstream and downstream edges was modified. The hybrid method based on Navier-Stokes and Perturbed Convective Wave Equation was used to solve the unidirectional coupling. The research showed a significant influence of the modification of the shape of the cavity edges on the generated noise. The change of downstream corner allowed for significant reduction of noise in the entire analysed band and allowed for the reduction of overall sound pressure level (OASPL) by 5 dB. Modifications of the upstream edge did not bring such differences, change in OASPL was up to 1 dB. The obtained spectra of the sound pressure level showed compliance with the calculated natural frequencies of the analysed object, as well as with some of the Rossiter modal frequencies, typical for the phenomena occurring in the cavities.
    Źródło:
    Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022301
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Numerical Study of The Heat Transfer Intensification Using High Amplitude Acoustic Waves
    Autorzy:
    Rulik, S.
    Wróblewski, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/177492.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cavity noise
    sound wave cooling
    flow over a cavity
    transient cooling
    blade cooling intensification
    Opis:
    The current practice in the efforts aiming to improve cooling conditions is to place emphasis on the application of non-stationary flow effects, such as the unsteady jet heat transfer or the heat transfer intensification by means of a high-amplitude oscillatory motion. The research presented in this paper follows this direction. A new concept is put forward to intensify the heat transfer in the cooling channels with the use of an acoustic wave generator. The acoustic wave is generated by a properly shaped fixed cavity or group of cavities. The sound generated by the cavity is a phenomenon analysed in various publications focused on the methods of its reduction. The phenomenon is related to the feedback mechanism between the vortices flowing from the leading edge and the acoustic waves generated within the cavity. The acoustic waves are generated by the interaction between the vortices and the cavity walls. Strong instabilities can be observed within a certain range of the free flow velocities. The investigations presented in this paper are oriented towards the use of the phenomenon for the purposes of the heat transfer process intensification. The first part of the work presents the numerical model used in the analysis, as well as its validation and comparison with empirical relations. The numerical model is constructed using the commercial CFD Ansys CFX-16.0 commercial program. The next part includes determining of the relationship between the amplitude of the acoustic oscillations and the cooling conditions within the cavity. The calculations are performed for various flow conditions.
    Źródło:
    Archives of Acoustics; 2018, 43, 1; 31-47
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of the elastic cavity walls on cavity flow noise
    Autorzy:
    Łojek, Paweł
    Czajka, Ireneusz
    Gołaś, Andrzej
    Suder-Dębska, Katarzyna
    Powiązania:
    https://bibliotekanauki.pl/articles/2146644.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    FSI
    Detached Eddy Simulations
    acoustic analogy
    cavity noise
    analogia akustyczna
    hałas generowany przez komorę
    Opis:
    In this study, computational fluid dynamics and computational aeroacoustics methods were used to investigate the influence of the elastic cavity walls on the noise generated by the flow over rectangular cavity. Two cases were considered and compared, one with rigid cavity walls, and one with elastic walls. In the latter case, the movement of the walls were solved by finite element modelling and coupled with CFD simulations. The noise generated by the flow over cavity was computed using Ffowcs Williams & Hawkings acoustic analogy. The increase of the sound pressure level for elastic walls case at frequency range of 1 kHz to 10 kHz is observed, compared to the rigid walls case.
    Źródło:
    Vibrations in Physical Systems; 2021, 32, 1; art. no. 2021109
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of cavity edges shape on flow induced noise
    Autorzy:
    Łojek, Paweł
    Suder-Dębska, Katarzyna
    Mach, Michał
    Powiązania:
    https://bibliotekanauki.pl/articles/2146642.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    aeroacoustics
    computational fluid dynamics
    cavity noise
    aeroakustyka
    obliczeniowa dynamika płynów
    hałas generowany przez komorę
    Opis:
    In this paper, impact of the cavity shape on flow-generated noise is analysed. As reference model, the classic rectangular cavity with perpendicular corners was used. The impact of both upstream and downstream edges was analyzed. In this paper, authors used hybrid method, where the flow was computed by means of Spalart-Allmaras Detached Eddy Simulations (DES) model, and the acoustic wave propagation was calculated by Curle acoustic analogy.
    Źródło:
    Vibrations in Physical Systems; 2021, 32, 1; art. no. 2021110
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Numerical Study of the Relation Between the Acoustic Generator Geometry and the Heat Transfer Conditions
    Autorzy:
    Rulik, S.
    Wróblewski, W.
    Rusin, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/140076.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cavity noise
    cavity cooling
    new cooling techniques
    acoustic cooling
    acoustic waves
    heat transfer in cavities
    thermoacoustics
    szum aerodynamiczny
    chłodzenie zewnętrzne
    nowe techniki chłodzenia
    chłodzenie akustyczne
    fale akustyczne
    przepływ ciepła
    termoakustyka
    Opis:
    Modern gas turbine systems operate in temperatures ranging from 1200°C to even 1500°C, which creates bigger problems related to the blade material thermal strength. In order to ensure appropriate protection of the turbine blades, a sophisticated cooling system is used. Current emphasis is placed on the application of non-stationary flow effects to improve cooling conditions, e.g., the unsteady-jet heat transfer or the heat transfer enhancement using high-amplitude oscillatory motion. The presented research follows a similar direction. A new concept is proposed of intensification of the heat transfer in the cooling channels with the use of an acoustic wave generator. The acoustic wave is generated by an appropriately shaped fixed cavity or group of cavities. The phenomenon is related to the coupling mechanism between the vortex shedding generated at the leading edge and the acoustic waves generated within the cavity area. Strong instabilities can be observed within a certain range of the free flow velocities. The presented study includes determination of the relationship between the amplitude of acoustic oscillations and the cooling conditions within the cavity. Different geometries of the acoustic generator are investigated. Calculations are also performed for variable flow conditions. The research presented in this paper is based on a numerical model prepared using the Ansys CFX-17.0 commercial CFD code.
    Źródło:
    Archive of Mechanical Engineering; 2018, LXV, 1; 5-26
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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