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Wyszukujesz frazę "aeroacoustic noise" wg kryterium: Temat

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    Wyświetlanie 1-3 z 3
    Tytuł:
    Application of hybrid CFD/CAA technique for modeling pressure fluctuations in transonic flows
    Autorzy:
    Dykas, S.
    Wróblewski, W.
    Rulik, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1955297.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Gdańska
    Tematy:
    transonic flow
    aeroacoustic noise
    hybrid technique
    Opis:
    Solving AeroAcoustics (CAA) problems by means of the Direct Numerical Simulation (DNS) or even the Large Eddy Simulation (LES) for a large computational domain is very time consuming and cannot be applied widely for engineering purposes. In this paper in-house CFD and CAA codes are presented. The in-house CFD code is based on the LES approach whereas the CAA code is an acoustic postprocessor solving non-linearized Euler equations for fluctuating (acoustic) variables. These codes are used to solve the pressure waves generated aerodynamically by a flow over a rectangular cavity and by the vortex street behind a turbine blade. The obtained results are discussed with respect to the application of the presented numerical techniques to pressure waves modeling in steam turbine stages.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2013, 17, 3-4; 145--154
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Noise radiation from circular rods at low-moderate Reynolds number
    Autorzy:
    Kopania, Joanna Maria
    Bogusławski, Grzegorz
    Gaj, Patryk
    Wójciak, Kamil
    Powiązania:
    https://bibliotekanauki.pl/articles/128113.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    aeroacoustic noise
    circular rod
    low Reynolds number
    hałas aeroakustyczny
    pręt kołowy
    niska liczba Reynoldsa
    Opis:
    The well-known dominant sources of airframe noise are associated with unsteadiness of separated and/or vortical flow regions around the high-lift system (flaps, slats) and the aircraft undercarriage (landing gear). Current practical landing gear noise prediction models are individual component - based, which means that the various components are divided into groups according to the frequency range, in which they predominantly radiate noise. Since the far-field noise spectra are approximately Strouhal - based, the emitted frequency is assumed to be directly related to their size: the large elements are responsible for the low frequency region of the spectra, and the small components for the high frequency region. On the basis of such understanding of the noise generation mechanism, the special configurations that lead to considerable noise suppression were proposed. One element of these configurations are rods with different shape and cross section. In this work the situation when circular rods are in area of laminar-turbulent flow were analysed. The measurements were carried out for single circular rod with different diameters to study the noise effect depended on Reynolds number. Far field noise for broad range of Reynolds numbers was also examined depending on distance from the source of noise.
    Źródło:
    Vibrations in Physical Systems; 2019, 30, 1; 1-8
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Research on Airflow Background Noise Suppression for Aeroacoustic Wind Tunnel Testing
    Autorzy:
    Li, Yuanwen
    Li, Min
    Feng, Daofang
    Yang, Debin
    Wei, Long
    Powiązania:
    https://bibliotekanauki.pl/articles/2141671.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    aeroacoustic measurement
    acoustic source localization
    EEMD; background noise suppression
    wind tunnel test.
    Opis:
    The microphone data collected in aeroacoustic wind tunnel test contains not only desired aeroacoustic signal but also background noise generated by the jet or the valve of the wind tunnel, so the desired aeroacoustic characteristics is difficult to be highlighted due to the low Signal-to-Noise Ratio (SNR). Classical cross spectral matrix removal can only reduce the microphone self-noise, but its effect is limited for jet noise. Therefore, an Airflow Background Noise Suppression method based on the Ensemble Empirical Mode Decomposition (ABNSEEMD) is proposed to eliminate the influence of background noise on aeroacoustic field reconstruction. The new method uses EEMD to adaptively separate the background noise in microphone data, which has good practicability for increasing SNR of aeroacoustic signal. A localization experiment was conducted by using two loudspeakers in wind tunnel with 80 m/s velocity. Results show that proposed method can filter out the background noise more effectively and improve the SNR of the loudspeakers signal compared with spectral subtraction and cepstrum methods. Moreover, the aeroacoustic field produced by a NACA EPPLER 862 STRUT airfoil model was also measured and reconstructed. Delay-and-sum beamforming maps of aeroacoustic source were displayed after the background noise was suppressed, which further demonstrates the proposed method’s advantage.
    Źródło:
    Archives of Acoustics; 2022, 47, 2; 241-257
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-3 z 3

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