Temat: computational simulation - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Fuzzy-based Description of Computational Complexity of Central Nervous Systems
Autorzy:: Prokopowicz, Piotr
Mikołajewski, Dariusz
Tyburek, Krzysztof
Kotlarz, Piotr
Powiązania:: https://bibliotekanauki.pl/articles/309535.pdf
Data publikacji:: 2020
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: cognitive deficit
cognitive functions
computational simulation
fuzzy descriptors
Opis:: Computational intelligence algorithms are currently capable of dealing with simple cognitive processes, but still remain inefficient compared with the human brain’s ability to learn from few exemplars or to analyze problems that have not been deﬁned in an explicit manner. Generalization and decision-making processes typically require an uncertainty model that is applied to the decision options while relying on the probability approach. Thus, models of such cognitive functions usually interact with reinforcement-based learning to simplify complex problems. Decision-makers are needed to choose from the decision options that are available, in order to ensure that the decision-makers’ choices are rational. They maximize the subjective overall utility expected, given by the outcomes in diﬀerent states and weighted with subjective beliefs about the occurrence of those states. Beliefs are captured by probabilities and new information is incorporated using the Bayes’ law. Fuzzy-based models described in this paper propose a diﬀerent – they may serve as a point of departure for a family of novel methods enabling more effective and neurobiologically reliable brain simulation that is based on fuzzy logic techniques and that turns out to be useful in both basic and applied sciences. The approach presented provides a valuable insight into understanding the aforementioned processes, doing that in a descriptive, fuzzy-based manner, without presenting a complex analysis.
Źródło:: Journal of Telecommunications and Information Technology; 2020, 3; 57-66
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Investigation of the flow conditions in a high-performance heat exchanger
Autorzy:: Łopata, S.
Ocłoń, P.
Powiązania:: https://bibliotekanauki.pl/articles/240227.pdf
Data publikacji:: 2010
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: awaria
symulacja komputerowa
wymiana ciepła
computational simulation
failure
heat exchange
Opis:: CFD (Computational Fluid Dynamics) computations are carried out in order to investigate the flow distribution and its influence on the heat transfer processes in the high-performance heat exchanger. The subject of this investigation is the classical model of the high-performance heat exchanger with elliptical tubes and rectangular fins. It is possible to find the flow domains where the heat transfer conditions are impaired due to the fully developed turbulent flow. Therefore, the considerable thermal loads occur that may cause the breakdown of the heat exchanger. The emphasis of this investigation is put on the zones and the locations where the tubes are not properly fed with liquid, that result in occurrence of cavitation.
Źródło:: Archives of Thermodynamics; 2010, 31, 3; 37-53
1231-0956
2083-6023
Pojawia się w:: Archives of Thermodynamics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Computational simulation of motion of a rescue module during its launching from ship at rough sea
Autorzy:: Dymarski, C.
Dymarski, P.
Powiązania:: https://bibliotekanauki.pl/articles/259483.pdf
Data publikacji:: 2014
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: lifeboat
rescue boat launch
innovation
launch ramp aft
computational model for simulation lifeboat
computational model for simulation
Opis:: This paper is a continuation of the work titled : “A computational model for simulation of motion of rescue module during its launching from stern ramp of a ship at rough sea”. It presents results of computer simulations of motion of a rescue module with embarked persons during its launching on rollers along stern ramp of a ship at rough sea. The simulations were conducted for a selected ship fitted with a launching ramp , for a few selected scenarios of sea conditions. It was assumed that during this operation the ship drifts across direction of wave propagation.
Źródło:: Polish Maritime Research; 2014, 3; 54-60
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A numerical model to simulate the motion of a lifesaving module during its launching from the ship’s stern ramp
Autorzy:: Dymarski, P.
Dymarski, C.
Powiązania:: https://bibliotekanauki.pl/articles/260530.pdf
Data publikacji:: 2014
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: lifeboat
rescue boat launch
innovation
launch ramp aft
computational model for simulation
Opis:: The article presents a numerical model of object motion in six degrees of freedom (DoF) which is intended to be used to simulate 3D motion of a lifesaving module during its launching from a ship using a stern ramp in rough sea. The model, of relatively high complexity, takes into account both the motion of the ship on water in changing sea conditions, and the relative motion of the ramp with respect to the ship. The motion of the ramp changes and strongly depends on its constructional and geometrical parameters. The presented model takes into account the displacement of the submerged part of the ramp, as well as its damping in the water and the interaction with the module moving on it. The results of test simulation of a module launching from the ship in still water are included.
Źródło:: Polish Maritime Research; 2014, 2; 34-40
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: CFD simulation of DEBORA boiling experiments
Autorzy:: Rzehak, R.
Krepper, E.
Powiązania:: https://bibliotekanauki.pl/articles/240154.pdf
Data publikacji:: 2012
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: obliczeniowa mechanika płynów
przechłodzenie
symulacja
computational fluid dynamics simulation
heat flux partitioning
subcooled flow boiling
two-fluid model
Opis:: In this work we investigate the present capabilities of computational fluid dynamics for wall boiling. The computational model used combines the Euler/Euler two-phase flow description with heat flux partitioning. This kind of modeling was previously applied to boiling water under high pressure conditions relevant to nuclear power systems. Similar conditions in terms of the relevant non-dimensional numbers have been realized in the DEBORA tests using dichlorodifluoromethane (R12) as the working fluid. This facilitated measurements of radial profiles for gas volume fraction, gas velocity, bubble size and liquid temperature as well as axial profiles of wall temperature. After reviewing the theoretical and experimental basis of correlations used in the ANSYS CFX model used for the calculations, we give a careful assessment of the necessary recalibrations to describe the DEBORA tests. The basic CFX model is validated by a detailed comparison to the experimental data for two selected test ca cases. Simulations with a single set of calibrated parameters are found to give reasonable quantitative agreement with the data for several tests within a certain range of conditions and reproduce the observed tendencies correctly. Several model refinements are then presented each of which is designed to improve one of the remaining deviations between simulation and measurements. Specifically we consider a homogeneous MUSIG model for the bubble size, modified bubble forces, a wall function for turbulent boiling flow and a partial slip boundary condition for the liquid phase. Finally, needs for further model developments are identified and promising directions discussed.
Źródło:: Archives of Thermodynamics; 2012, 33, 1; 107-122
1231-0956
2083-6023
Pojawia się w:: Archives of Thermodynamics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Wpływ uproszczeń w badaniach symulacyjnych zderzeń pocisków z tarczą na dokładność wyników
Influence of simulation simplifications on results accuracy
Autorzy:: Stanisławek, S.
Morka, A.
Niezgoda, T.
Powiązania:: https://bibliotekanauki.pl/articles/209401.pdf
Data publikacji:: 2013
Wydawca:: Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:: mechanika komputerowa
symulacja
computational mechanics
simulation
Opis:: Artykuł omawia zagadnienie możliwości stosowania określonych uproszczeń w symulacji komputerowej. Stanowi on niezbędny warsztat dla każdego badacza stosującego opisane sposoby modelowania. Weryfikacja uproszczeń numerycznych polegała na przeprowadzeniu trzech testów zderzeniowych dla rdzenia pocisku 7,62 × 51 WC oraz czwartej symulacji polegającej na porównaniu efektów uderzenia pełnego modelu pocisku oraz jedynie jego rdzenia. Opracowane modele tarczy symulowały materiał stalowy z wprowadzonymi typowymi parametrami, natomiast pocisk był opisany modelem Johnsona-Cooka. Prędkość początkowa pocisku wynosiła 854 m/s, zaś tarcza pozostawała nieruchoma i zamocowana w płaszczyźnie prostopadłej do kierunku lotu. Opisane badania potwierdzają możliwość stosowania modelu materiału nieodkształcalnego oraz sprężystego do uproszczonego opisu ciał materialnych. Pozwala to na uproszczenie i przyspieszenie obliczeń numerycznych w sytuacjach, gdzie materiały zderzających się ciał mają znacznie różne właściwości mechaniczne. Z dużą ostrożnością powinno się odnosić do odczytywania sił rejestrowanych na ściance nieodkształcalnej. Analiza sił oraz energii pokazuje natomiast, że sabot i płaszcz pocisku nie odgrywają zasadniczej roli przy uderzeniu w nieruchomą tarczę. Doznaje ona większego popędu, jednak nie jest to różnica zasadnicza.
The paper presents the possibility of applying certain simplifications for computer simulations. It is the essential knowledge for each scientist employing the described methods of modelling. Verification of numerical simplifications consisted in conducting three impact tests for a 7.62 × 51 WC projectile core and a forth one which referred to a comparison of a full model of the penetrator with its core only. The target was described with a simple steel material while the projectile with an advanced Johnson-Cook model. Projectile initial speed was 854 m/s while a target remained motionless and fixed in a plane perpendicular to the motion direction. The performed tests confirm the possibility of using rigid and elastic materials for a simplified material body description. It allows simplification and shortening of computational time when materials are characterized by very different strength. However, a user should be very careful when analyzing the forces recorded on a rigid wall. Furthermore, analysis of the forces and energies shows that both a sabot and a jacket do not play a significant role during the impact into a motionless target. It register a bigger force impulse but it is not a substantial difference.
Źródło:: Biuletyn Wojskowej Akademii Technicznej; 2013, 62, 3; 137-143
1234-5865
Pojawia się w:: Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: A computational fluid flow analysis of a disc valve system
Autorzy:: Czop, P.
Śliwa, P.
Gniłka, J.
Gąsiorek, D.
Wszołek, G.
Powiązania:: https://bibliotekanauki.pl/articles/244640.pdf
Data publikacji:: 2011
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: valve system
computational fluid flow analysis
simulation
Opis:: Noise concerns in shock absorbers can be divided into two categories. The first is fluid flow noise, or “swish noise”, caused by the oil being forced through openings in the valves. The type and temperature of the oil, its velocity and the orifice geometry all have an effect on this. In addition, the structural design of the shock absorber shell may either reduce or amplify the noise. The second type of shock absorber noise is often described as regular operational noise or “chuckle noise”. It can be observed in vehicles during low-displacement, higher-frequency events, such as driving over a slightly rough road. This effect measurable as a force discontinuity into the vehicle and can come from a number of sources in the shock absorber, e.g. hydraulic transitions. It is often traceable to the valve discs closing and opening, but can also be caused by cavitation/aeration in the oil and air being pulled through the valves. The work on noise improvement reported in this paper has been started using conventional shock absorbers to be extended and will cover in the future variable damping shock systems as well. The paper gives an overview about the configurations of a typical valve system including three basic regimes of operation, which correspond to the amount of oil flowing through a valve cavity. The aim of this work was to propose a finite element fluid flow model, which can be used in order to reduce the velocity of fluid flow through a cavity of a shock absorber valve. High flow velocity can cause high-content frequency vibrations and, in turn, audible noise. The model will be used for initial screening of new valve concepts and on the other hand to improve the currently use ones.
Źródło:: Journal of KONES; 2011, 18, 1; 117-122
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: CFD computation of the savonius rotor
Autorzy:: Rogowski, K.
Maroński, R.
Powiązania:: https://bibliotekanauki.pl/articles/280680.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: vertical axis wind turbine
simulation
computational fluid dynamics (CFD)
Opis:: In this paper, Computational Fluid Dynamics (CFD) analysis of a two-dimensional two- -bucket Savonius rotor, using ANSYS Fluent solver, is presented. Computational methods of fluid dynamics are used to estimate the aerodynamic forces acting on the rotor, the torque and the power extracted by the Savonius rotor. In addition, an analysis of the results for different turbulence models is performed. Numerical investigations are compared with the experiment of the Sandia National Laboratories.
Źródło:: Journal of Theoretical and Applied Mechanics; 2015, 53, 1; 37-45
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The Methodology of Analysis on Geometrical Changes of a Mixed Zone in Resistance-Heated Samples
Autorzy:: Dębiński, T.
Głowacki, M.
Hojny, M.
Powiązania:: https://bibliotekanauki.pl/articles/353320.pdf
Data publikacji:: 2019
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: mixed zone
resistance heating
computer simulation
visualization
computational geometry
Opis:: The article presents the use of computer graphics methods and computational geometry for the analysis on changes of geometrical parameters for a mixed zone in resistance-heated samples. To perform the physical simulation series of resistance heating process, the Gleeble 3800 physical simulator, located in the Institute for Ferrous Metallurgy in Gliwice, was used. The paper presents a description of the test stand and the method for performing the experiment. The numerical model is based on the Fourier-Kirchoff differential equation for unsteady heat flow with an internal volumetric heat source. In the case of direct heating of the sample, geometrical parameters of the remelting zone change rapidly. The described methodology of using shape descriptors to characterise the studied zone during the process allows to parametrise the heat influence zones. The shape descriptors were used for the chosen for characteristic timing steps of the simulation, which allowed the authors to describe the changes of the studied parameters as a function of temperature. Additionally, to determine the impact of external factors, the remelting zone parameters were estimated for two types of grips holding the sample, so-called hot grips of a shorter contact area with the sample, and so-called cold grips. Based on the collected data, conclusions were drawn on the impact of the process parameters on the localisation and shape of the mushy zone.
Źródło:: Archives of Metallurgy and Materials; 2019, 64, 4; 1463-1470
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Computational Fluid Dynamics Modeling of Residence Time Distribution in a Field-Scale Horizontal Subsurface Flow Constructed Wetland with Palm Kernel Shell as Substrate
Autorzy:: Okoye, Nelson Mbanefo
Madubuike, Chimaobi Nnaemeka
Nwuba, Ifeanyi Uba
Orakwe, Louis Chukwuemeka
Ugwuishiwu, O. Boniface
Powiązania:: https://bibliotekanauki.pl/articles/1163287.pdf
Data publikacji:: 2018
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:: COMSOL
Computational Fluid Dynamics
Constructed Wetland
Simulation Modelling
Wastewater Treatment
Opis:: The hydraulic performance of constructed wetlands is often compromised by hydraulic problems. Therefore, the development of an appropriate simulation model to reliably predict how various modifications of bed design and configurations might affect performance will facilitate the design of efficient systems. The aim of this research work is to determine distribution of residence time in a field-scale horizontal subsurface flow constructed wetland with Palm Kernel Shell as substrate. The governing equations of flow in porous media and transport of diluted species were solved using COMSOL Multiphysics 5.3a. The result was validated using experimental data and the model result showed good agreement with a correlation coefficient of 0.99. Alternative wetland designs were assessed for the same flow conditions. The results revealed that a two cell wetland improved short-circuiting flow paths.
Źródło:: World Scientific News; 2018, 109; 60-70
2392-2192
Pojawia się w:: World Scientific News
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Military route planning in battlefield simulation: effectiveness problems and potential solutions
Autorzy:: Tarapata, Z.
Powiązania:: https://bibliotekanauki.pl/articles/309343.pdf
Data publikacji:: 2003
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: battlefield simulation
route planning
shortest paths
effectiveness problems
computational complexity
Opis:: Path searching is challenging problem in many domains such as simulation war games, robotics, military mission planning, computer generated forces (CGF), etc. Effectiveness problems in military route planning are related both with terrain modelling and path planning algorithms. These problems may be considered from the point of view of many criterions. It seems that two criterions are the most important: quality of terrain reflection in the terrain model and computational complexity of the on(off)-line path planning algorithm. The paper deals with two above indicated problems of route planning effectiveness. Comparison of approaches used in route planning is presented. The hybrid, terrain merging-based and partial path planning, approach for route planning in dynamically changed environment during simulation is described. It significantly increase effectiveness of route planning process. The computational complexity of the method is given and some discussion for using the method in the battlefield simulation is conducted. In order to estimate how many times faster we can compute problem for finding shortest path in network with n big squares (b-nodes) with relation to problem for finding shortest path in the network with V small squares (s-nodes) acceleration function is defined and optimized.
Źródło:: Journal of Telecommunications and Information Technology; 2003, 4; 47-56
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Jet and droplet breakup modelling approaches
Autorzy:: Kapusta, Ł. J.
Jaworski, P.
Kowalski, J.
Powiązania:: https://bibliotekanauki.pl/articles/245813.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: spray
modelling
simulation
breakup
injection
CFD
computational fluid dynamics (CFD)
Opis:: Three-dimensional computational fluid dynamics (CFD) plays important role in engines development. The mixture formation in a direct-injection piston engines poses a huge challenge in successful simulations of the engine processes. It is due to the fact that the spray as a two-phase flow complicates the computational process. Moreover, this multiphase flow is not uniform. Three main zones, depending on the distance from the nozzle exit are visible when a liquid is injected. Very dense so called “thick” in a direct vicinity of the injector hole, than “thin” as a result of pri-mary breakup downstream the injector and finally in the certain distance from the injector appears “very thin” region as a result of secondary breakup. It is important to take into account that the liquid phase in various regimes behaves differently and is under influence of different phenomena. The modelling approach needs to take in to consideration all those elements. This paper focuses on presentation of the theory and numerical models for primary and secondary breakup phenomena. The primary breakup is a process that results from a combination of three mechanisms: turbu-lence within liquid phase, implosion of cavitation’s bubbles and aerodynamic forces acting on a liquid jet. Secondary breakup regime occurs mainly due to the aerodynamic interactions between the liquid and the gaseous phase.
Źródło:: Journal of KONES; 2015, 22, 3; 83-90
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: A markovian-based simulation model for the evolution of employees’ emotional states during an organizational change
Model symulacyjny w oparciu o model markoviana, ewolucji stanów emocjonalnych pracowników podczas zmiany organizacyjnej
Autorzy:: Castillo, Cristian
Fernandez, Vicenc
Lordan, Oriol
Powiązania:: https://bibliotekanauki.pl/articles/2021118.pdf
Data publikacji:: 2021
Wydawca:: Politechnika Częstochowska
Tematy:: simulation
computational model
organizational change
symulacja
model obliczeniowy
zmiana organizacyjna
Opis:: This study aims to create a simulation model with which to analyse the spread of emotional states among the employees of an organization. The model takes into account the fact that workers are influenced by their co-workers and supervisors, and simultaneously analyses these interactions. The design of the simulation model follows a standard procedure: problem definition, data collection and configuration of model parameters, conceptual model, testing of the programmed model, and analysis of the results of the simulation. The resulting simulation model makes a novel contribution to the literature by providing social sciences researchers with a simple and efficient method of analysing the evolution and propagation of emotional states during an organizational change. This kind of approach is useful for research involving the simultaneous study of interaction between a number of employees.
Niniejsze badanie ma na celu stworzenie modelu symulacyjnego do analizy rozprzestrzeniania się stanów emocjonalnych wśród pracowników organizacji. Model uwzględnia fakt, że na pracowników wpływają ich współpracownicy i przełożeni, jednocześnie analizując te interakcje. Projektowanie modelu symulacyjnego odbywa się według standardowej procedury: definiowanie problemu, zbieranie danych i konfiguracja parametrów modelu, model koncepcyjny, testowanie zaprogramowanego modelu oraz analiza wyników symulacji. Powstały model symulacyjny wnosi nowatorski wkład do literatury, zapewniając badaczom nauk społecznych prostą i skuteczną metodę analizy ewolucji i propagacji stanów emocjonalnych podczas zmiany organizacyjnej. Takie podejście jest przydatne w badaniach polegających na jednoczesnym badaniu interakcji między wieloma pracownikami.
Źródło:: Polish Journal of Management Studies; 2021, 23, 1; 119-135
2081-7452
Pojawia się w:: Polish Journal of Management Studies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: The Use of Fuzzy Systems for Forecasting the Hardenability of Steel
Autorzy:: Sitek, W.
Irla, A.
Powiązania:: https://bibliotekanauki.pl/articles/356485.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: computational material science
artificial intelligence methods
materials design steels
modelling
simulation
Opis:: The goal of the research carried out was to develop the fuzzy systems, allowing the determination of the Jominy hardenability curve based on the chemical composition of structural steels for quenching and tempering. Fuzzy system was created to calculate hardness of the steel, based on the alloying elements concentrations, and to forecast the hardenability curves. This was done based on information from the PN-EN 10083-3: 2008. Examples of hardenability curves calculated for exemplar steels were presented. Results of the research confirmed that fuzzy systems are a useful tool in evaluation the effect of alloying elements on the properties of materials compared to conventional methods. It has been demonstrated the practical usefulness of the developed models which allows forecasting the steels’ Jominy hardenability curve.
Źródło:: Archives of Metallurgy and Materials; 2016, 61, 2A; 797-802
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Applicability of flow simulation models to the case of radial inflow onto a rotating core
Autorzy:: Biernacki, R.
Powiązania:: https://bibliotekanauki.pl/articles/1955813.pdf
Data publikacji:: 2001
Wydawca:: Politechnika Gdańska
Tematy:: turbulent flow
numerical flow simulation
flow simulation models
steam turbines
turbine inlet
computational fluid dynamics CFD
Opis:: The paper presents the results of fluid flow simulations carried out by means of the FIDAP7.6 program (a fluid dynamics FEM package) for the case of radial inflow onto a rotating shaft. The particular geometric configuration has been chosen to resemble a generalized inlet chamber of twin low-pressure steam turbines, but with the axial outlet section extended to allow better observation of flow instabilities in that region. The calculations were carried out for the same channel geometry for both compressible and incompressible flow, using the same or slightly varying boundary conditions. Extensive variation in non-physical parameters of the model was explored, such as applying different meshes over the region, as well as utilizing different turbulence and upwinding models. The intent of this research was to evaluate the relative applicability of the various available flow models to the simulation of axisymmetric flows with steep velocity gradients, and to discover the limitations of these models. The calculations have in fact established significant differences in the behavior of the simulated flow for the different meshes and models. Some results were characterized by extensive areas of recirculating flow whereas others, for the same boundary conditions, showed no recirculation. Correct near-wall meshing as well as the choice of the upwinding scheme were established as the critical factors in this regard. There was also noticeable variation in outlet velocity profiles. An extensive zone of separation within the investigated channel as well as a standing annular vortex near the point of stagnation are flow features of some interest. These patterns of flow change in response to the changing non-physical parameters; the separation zone in particular is absent or slow to develop under some setups. The influence of inflow parameters, the initial velocity distribution and turbulent intensity in particular, on flow behavior in contact with the rotating shaft have also been an area of investigation, as these are often defined with considerable uncertainty in practical applications. It was observed that some latitude in assuming these parameters did not significantly alter the relevant flow parameters at outlet (the velocity and pressure distributions), although it did induce variation in other aspects of the flow (such as the extent of the standing vortex).
Źródło:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 2; 141-154
1428-6394
Pojawia się w:: TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:: Biblioteka Nauki

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