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Wyszukujesz frazę "FLOW-3D" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
A turbulence model for 3-d flows with anisotropic structure of turbulence
Autorzy:
Czernuszenko, W.
Rylov, A.
Powiązania:
https://bibliotekanauki.pl/articles/241364.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
3D flow
mathematical model
numerical simulation
open channel flow
turbulence model
Opis:
A new turbulence model for flows in open channels with compound cross-sections is presented. The structure of turbulence in these channels can be anisotropic. This structure is described by the turbulent stress tensor that is presented here as the sum of two tensors, namely, normal and shear stress tensors. The normal and shear turbulent stresses are expressed by the turbulence intensities and the mixing length tensor (MLT), respectively. The turbulence intensities can be learned from measurements or another suitable approaches. One such approach that allows calculating the main component of the normal stresses is presented in the paper. The components of MLT are defined based on a new concept of generic mixing length (GML). The generic mixing length is assumed to depend on both distances; from the nearest wall and from the water surface. To demonstrate how the new model works the basic hydrodynamic equations (parabolic approximation of Reynolds equations) together with the turbulence model are solved. The well-known Patankar and Spalding (1972) algorithm was used when solving these equations. A series of numerical simulations were performed for different components of MLT and different channel geometries.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 4; 303-320
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of 3D flow in axial turbomachines
Autorzy:
Yershov, S.
Rusanov, A. V.
Gardzielewicz, A.
Lampart, P.
Świrdyczuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/1953978.pdf
Data publikacji:
1998
Wydawca:
Politechnika Gdańska
Tematy:
numerical simulation
axial turbomachines
3D flow
3D viscous compressible flow
Navier-Stokes equation
ENO reconstruction
computational efficiency
computational fluid dynamics CFD
Godunov-type upwind differencing
Opis:
The paper is intended to describe a method for the calculation of 3D viscous compressible (subsonic or supersonic) flow in axial turbomachines described in the form of thin-layer Reynolds-averaged Navier-Stokes equations. The method draws on Godunov-type upwind differencing and ENO reconstruction suggested by Harten (1987), so as to assure monotonicity preservation and high accuracy of computational results. The computational efficiency is achieved thanks to the implementation of a simplified H-type multi-grid approach and delta -form implicit step. Turbulent effects are simulated with the help of a modified algebraic model of Baldwin-Lomax (1978). This method was at the foundation of a computer code-a complex software package to calculate 3D flow in multi-stage turbomachines that allows us to obtain local characteristics, like temperature, pressure, density or velocity distributions, as well as global characteristics, such as flow rates, stage reaction, flow efficiency for the considered turbine/compressor stage. The paper also gives selected results of computation of a number of turbomachinery cascades, showing that these results agree reasonably well with the available experimental data.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1998, 2, 2; 319-347
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of 3D flow in VKI-Genoa turbine cascade including laminar-turbulent transition
Autorzy:
Yerschov, S.
Derevyanko, A.
Yakovlev, V.
Gryzun, M.
Powiązania:
https://bibliotekanauki.pl/articles/1938601.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska
Tematy:
numerical simulation
3D flow
turbine cascade
laminar-turbulent transition
turbulence kinetic energy
secondary flows
losses
Opis:
This study presents a numerical simulation of a 3D viscous flow in the VKI-Genoa cascade taking into account the laminar-turbulent transition. The numerical simulation is performed using the Reynolds-averaged Navier-Stokes equations and the two-equation k-ω SST turbulence model. The algebraic Production Term Modification model is used for modeling the laminar-turbulent transition. Computations of both fully turbulent and transitional flows are carried out. The Mach number contours, the turbulence kinetic energy, the entropy function as well as the limiting streamlines are presented. Our numerical results demonstrate the influence of the laminar-turbulent transition on the secondary flow pattern. The comparison between the present computational results and the existing experimental and numerical data shows that the proposed approach reflects sufficiently the physics of the laminar-turbulent transition in turbine cascades.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2016, 20, 1; 43-61
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Studies on a Three-dimensional Flow Field in Four-Roller Compact Spinning with a Guiding Device
Badania numeryczne trójwymiarowego pola przepływu w czterowałkowym aparacie rozciągowym przędzarki kompaktowej wyposażonej w urządzenie prowadzące
Autorzy:
Liu, X.
Xie, C.
Su, X.
Mei, H.
Powiązania:
https://bibliotekanauki.pl/articles/233593.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
four-roller compact spinning
guiding device
3D flow field
numerical simulation
fluent
kompaktowy układ czterorolkowy
urządzenie prowadzące
pole przepływu 3D
symulacja numeryczna
analiza pola przepływu
Opis:
Research on the flow field in the fibre-converging zone is always the emphasis and difficulty of compact spinning. Therefore in this work numerical studies on the three-dimensional flow field in four-roller compact spinning with a guiding device were carried out using Fluent software. First a three-dimensional physical model of the fibre-converging zone was obtained using AutoCAD software. Then numerical simulations of the three-dimensional flow field in four-roller compact spinning with and without a guiding device were presented, respectively, using Fluent software. It was shown that the negative pressure is chiefly concentrated near the air-suction flume, and the velocity reaches the maximum on the centre line. Comparing with the flow field in compact spinning without a guiding device, the effective range of negative pressure in four-roller compact spinning with a guiding device increases significantly and negative pressure use efficiency improves accordingly. Furthermore the optimal installation position of the guiding device was studied, and it was shown that the optimal installation position is closely related to the linear density of the spun yarn. Finally the theoretical results obtained were illustrated by experiments.
Podstawową trudnością w przędzeniu kompaktowym jest analiza pola przepływu strumienia włókien, którą przeprowadzono korzystając ze specjalnego oprogramowania – Fluent Software. Wstępnie opracowano model fizyczny procesu korzystając z systemu AutoCAD. Wykazano, że podciśnienie jest głównie skoncentrowane w pobliżu kanałów zasysających i prędkość osiąga swoje maksimum w centrum układu. Wykazano korzyści z zastosowania układu czterorolkowego w porównaniu do układu klasycznego i optymalne pozycje rozmieszczenia ściśle uzależnione od masy liniowej produkowanej przędzy. Uzyskane obliczenia teoretyczne porównano z wynikami praktycznymi.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 6 (102); 50-57
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation and modification of 3D flow phenomena in an axial flow fan
Autorzy:
Elhadi, E. E.
Keqi, W.
Powiązania:
https://bibliotekanauki.pl/articles/1954658.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
axial flow fan
vortex
stagger angle
numerical simulation
3D
Opis:
This work aims to study and analyze the behavior of flow in an axial flow fan using numerical simulation based on solving Reynolds-averaged Navier-Stokes equations coupled with a modified Spalart-Allaras turbulence model. In the present work, different flow phenomena occuring in an axial flow fan were presented and interpreted at different design conditions and at different regions, with special concern to the rotor exit and stator regions. Large vortices and reverse flow at the stator suction side were observed under high loading conditions. These are mainly due to radial and centrifugal effects in the fluid due to a decreasing flow rate. To avoid this type of flow, the stator flow pattern has been modified using a new stator blade. This blade was designed by changing the stator stagger angle by 10o in the radial direction. This study indicates that the flow in the modified stator region behaves well and gives better performance than that obtained when using a baseline stator, especially under high loading conditions. This study also indicates that the stator stagger angle has a significant effect on modifying the fan performance.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 2; 199-213
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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