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Wyszukujesz frazę "hydraulic modelling" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Impact of mesh quality on the numerical estimation of saturated water conductivity of pore media
Autorzy:
Gackiewicz, B.
Lamorski, K.
Slawiński, C.
Hsu, S.-Y.
Chang, L.-C.
Powiązania:
https://bibliotekanauki.pl/articles/2082923.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
porous media
numerical modelling
hydraulic
conductivity
mesh accuracy
Opis:
The numerical modelling of transport phenomena in porous media often requires a compromise between grid precision and the accuracy of simulation results. This study demonstrates the impact of errors on the accuracy of the reproduction of the actual pore space by the numerical grid on the estimated values of the saturated water conductivity. Four types of computational grids with varying levels of complexity were prepared for each of the 12 tomographic images of the porous specimens. The specific surfaces and total porosities were calculated for each of the meshes and compared with those parameters calculated for binarized tomographic images. Simulations of steady flow were performed on the computational grids, and the saturated water conductivity values were calculated. It has been shown that an insufficiently accurate mesh only reproduces the largest pore spaces in the analysed sample, which most often leads to an underestimation of the water conductivity coefficient. The following criterion for the optimal accuracy of the computational grid is proposed, it is based on the voxel size of the tomographic images of the porous media: the minimum size of the cell in the mesh used for simulations has to be at most two times the size of the voxel used in the tomographic scans of the porous medium.
Źródło:
International Agrophysics; 2020, 34, 4; 473-483
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes
Autorzy:
Szymkiewicz, A.
Tisler, W.
Burzyński, K.
Powiązania:
https://bibliotekanauki.pl/articles/94209.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
numerical modelling
Richards' equation
hydraulic conductivity
modelowanie numeryczne
równanie Richardsa
przewodnictwo hydrauliczne
Opis:
Flow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions), water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighbouring nodes or cells of the numerical grid. The present paper discusses application of the computer simulation code VS2DI to three test problems concerning infiltration into an initially dry medium, using various methods for inter-cell conductivity calculation (arithmetic mean, geometric mean and upstream weighting). It is shown that the influence of the averaging method can be very large for coarse grid, but that it diminishes as cell size decreases. Overall, the arithmetic average produced the most reliable results for coarse grids. Moreover, the difference between results obtained with various methods is a convenient indicator of the adequacy of grid refinement.
Źródło:
Geologos; 2015, 21, 3; 161-167
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Numerical Study of Non-hydrostatic Shallow Flows in Open Channels
Autorzy:
Zerihun, Y. T.
Powiązania:
https://bibliotekanauki.pl/articles/240980.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
turbulent flow
numerical modelling
non-hydrostatic pressure
rapidly-varied flow
hydraulic structures
Opis:
The flow field of many practical open channel flow problems, e.g. flow over natural bed forms or hydraulic structures, is characterised by curved streamlines that result in a non-hydrostatic pressure distribution. The essential vertical details of such a flow field need to be accounted for, so as to be able to treat the complex transition between hydrostatic and non-hydrostatic flow regimes. Apparently, the shallow-water equations, which assume a mild longitudinal slope and negligible vertical acceleration, are inappropriate to analyse these types of problems. Besides, most of the current Boussinesq-type models do not consider the effects of turbulence. A novel approach, stemming from the vertical integration of the Reynolds-averaged Navier-Stokes equations, is applied herein to develop a non-hydrostatic model which includes terms accounting for the effective stresses arising from the turbulent characteristics of the flow. The feasibility of the proposed model is examined by simulating flow situations that involve non-hydrostatic pressure and/or nonuniform velocity distributions. The computational results for free-surface and bed pressure profiles exhibit good correlations with experimental data, demonstrating that the present model is capable of simulating the salient features of free-surface flows over sharply-curved overflow structures and rigid-bed dunes.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2017, 64, 1; 17-35
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality improvement of a safety valve with the use of numerical and experimental studies
Autorzy:
Filo, Grzegorz
Domagała, Mariusz
Lempa, Paweł
Fabiś-Domagała, Joanna
Kwiatkowski, Dominik
Momeni, Hassan
Powiązania:
https://bibliotekanauki.pl/articles/104055.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
hydraulic system protection
safety valve
relief valve
numerical modelling
test bench experiments
układ hydrauliczny
zawór bezpieczeństwa
zawór nadmiarowy
modelowanie numeryczne
testy eksperymentalne
Opis:
This article presents results of numerical modelling, simulation and test bench experiments of a hydraulic direct-acting relief valve was used as a safety valve. The analyzed safety valve was placed in a system consisting of a fixed-speed pump, a control valve, a hydraulic cylinder as an actuator and a second pressure valve in the load line used as a payload generator for the cylinder. In the first step mathematical model of the system was formulated in the form of a system of ordinary differential equations. Next, simulation model was created in Matlab/Simulink. Simulations were carried out for different values of the actuator payload. The obtained results include time series of pressure, flow rate and displacement of the actuator piston. In order to confirm simulation results, a test bench was built and series of experiments were carried out. High compliance of simulation and laboratory results was obtained. It was confirmed that the proposed solution with the relief valve used as a safety valve fulfills its task of protecting the hydraulic system from excessive pressure increase.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 378-385
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of fluid flow inside the flow control valve
Autorzy:
Domagała, Mariusz
Momeni, Hassan
Fabis-Domagała, Joanna
Krawczyk, Mariusz
Filo, Grzegorz
Bikass, Saeed
Powiązania:
https://bibliotekanauki.pl/articles/104138.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
hydraulic system protection
safety valve
relief valve
numerical modelling
test bench experiments
układ hydrauliczny
zawór bezpieczeństwa
zawór nadmiarowy
modelowanie numeryczne
eksperyment badawczy
Opis:
Hydraulic valves are widely used in many branches and they are still developed and improved. Due to the problem with verification of flow phenomena which appears during valves operation numerical simulations methods are tools which allows to improved valves design. This paper presents numerical simulation of fluid flow inside flow control valve.
Źródło:
Quality Production Improvement - QPI; 2019, 1, 1; 394-399
2657-8603
Pojawia się w:
Quality Production Improvement - QPI
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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