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Wyszukujesz frazę "Reynolds averaged Navier–Stokes" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Experimental and numerical determination of the hydrodynamic coefficients of an autonomous underwater vehicle
Autorzy:
Sakaki, Abdollah
Kerdabadi, Mohsen Sadeghian
Powiązania:
https://bibliotekanauki.pl/articles/135543.pdf
Data publikacji:
2020
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
Reynolds averaged Navier–Stokes
computational fluid dynamics
linear coefficients
non-linear coefficients
underwater vehicle
Opis:
Computational fluid dynamics (CFD) has progressed rapidly in the past fifty years and is now used in many industrial fields, such as air, space, and marine engineering. CFD has an irreplaceable role in marine design and scientific research, and its applications within this field continue to grow with the development of computers. CFD is used to quickly and inexpensively simulate fluid behaviour using the Reynolds Averaged Navier–Stokes (RANS) equations to calculate hydrodynamic coefficients, which are needed in manoeuvrability studies of underwater vehicles (UWV). Here, these computations are performed for six geometrical shapes that represent typical autonomous underwater vehicles (AUVs) currently in use. Resistance test simulations at up to 20o drift angles were conducted for AUVs with different length-to-diameter ratios. The results were compared with the experimental data and current quasi-experimental relationships, which suggested that the CFD predictions were adequately precise and accurate. These predictions indicated that there was a non-linear relationship between forces and moments and the lateral speed. Moreover, both linear and non-linear hydrodynamic coefficients were calculated.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2020, 62 (134); 124-135
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation of a flow channel to investigate velocity profiles of friction-reducing ship coatings
Autorzy:
Weisheit, J.
Schneider, V. E.
Serr, J. M.
Hagemeister, N.
Oeffner, J.
Powiązania:
https://bibliotekanauki.pl/articles/1841545.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
ship coatings
flow Channel
vessel velocity
laser Doppler velocimeter
computational fluid dynamics
AIRCOAT project
reynolds averaged navier stokes
measurement volume
Opis:
Reducing friction with specialised hull coatings or air lubrication technologies has a potential reducing energy consumption and emissions in shipping. The EU project AIRCOAT combines both by developing a passive air lubrication technology inspired by nature that is implemented on a self-adhesive foil system. Besides validating the friction reduction it is of high interest to understand the underlying mechanism that causes the reduction. Therefore, a flow channel was designed, that creates a stationary turbulent flow within a square duct allowing for non-invasive measurements by laser doppler velocimetry. The high spatial resolution of the laser device makes recording velocity profiles within the boundary layer down to the viscous sublayer possible. Determination of the wall shear stress τ enables direct comparison of different friction reduction experiments. In this paper we validate the methodology by determining the velocity profile of the flat channel wall (without coatings). We further use the results to validate a CFD model in created in OpenFOAM. We find that velocities along the longitudinal axis are generally in good agreement between numerical and experimental investigations.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2021, 15, 1; 225-231
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementation of turbulence damping in the OpenFOAM multiphase flow solver interFoam
Autorzy:
Polansky, Jiri
Schmelter, Sonja
Powiązania:
https://bibliotekanauki.pl/articles/2091357.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multiphase flow
stratified flow
turbulence damping
computational fluid dynamics
OpenFOAM
Reynolds-averaged Navier–Stokes
Detached Eddy Simulation
Delayed Detached Eddy Simulation
Opis:
In the presented work Egorov’s approach (adding a source term to the ω-equation in the k-ω model, which mimics the damping of turbulence close to a solid wall) was implemented in on the subclass of shear stress transport models. Hence, turbulence damping is available for all shear stress transport type models, including hybrid models that are based on the ω-equation. It is shown that turbulence damping improves the prediction of the axial velocity profile not only for Reynolds-averaged Navier–Stokes simulation but also for detached eddy simulation and delayed detached eddy simulation models. Furthermore, it leads to a more realistic estimation of the pressure drop and, hence, to a more correct prediction of the liquid level. In this paper, simulation results for four different turbulence models are presented and validated by comparison with experimental data. Furthermore, the influence of the magnitude of the damping factor on the pressure drop in the channel is investigated for a variety of different gas-to-liquid flow rate ratios. These investigations show that higher gas-to-liquid flow rate ratios require higher damping factors to correctly predict the pressure drop. In the end, advice is formulated on how an appropriate damping factor can be determined for a specific test case.
Źródło:
Archives of Thermodynamics; 2022, 43, 1; 21--43
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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