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    Wyświetlanie 1-33 z 33
    Tytuł:
    Modeling of fluid flow in microgap considering the boundary change of dynamic viscosity
    Modelirovanie techenija zhidkosti v mikrozazore s uchetom granichnogo izmenenija dinamicheskojj vjazkosti
    Autorzy:
    Sokolova, Y.
    Rasskazova, Y.
    Krol, O.
    Sokolov, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/792974.pdf
    Data publikacji:
    2016
    Wydawca:
    Komisja Motoryzacji i Energetyki Rolnictwa
    Tematy:
    dynamic viscosity
    fluid flow
    flow velocity distribution
    viscous fluid
    gap
    distribution model
    Źródło:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2016, 16, 2
    1641-7739
    Pojawia się w:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Shape sensitivity analysis of time-dependent flows of incompressible non-Newtonian fluids
    Autorzy:
    Sokołowski, J.
    Stebel, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/206105.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    shape optimization
    shape gradient
    incompressible viscous fluid
    Navier-Stokes equations
    Opis:
    We study the shape differentiability of a cost function for the flow of an incompressible viscous fluid of power-law type. The fluid is confined to a bounded planar domain surrounding an obstacle. For smooth perturbations of the shape of the obstacle we express the shape gradient of the cost function which can be subsequently used to improve the initial design.
    Źródło:
    Control and Cybernetics; 2011, 40, 4; 1077-1097
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Lattice Boltzmann method for fluid mixing: a comparison with the finite element method
    Autorzy:
    Egidi, N.
    Misici, L.
    Piergallini, R.
    Tosi, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/1955715.pdf
    Data publikacji:
    2004
    Wydawca:
    Politechnika Gdańska
    Tematy:
    lattice Boltzmann method
    incompressible viscous fluid mixing
    Reynolds number
    numerical simulation
    Opis:
    In this article we study three-dimensional mixing of an incompressible viscous fluid subjected to the force of rotating blades in a vessel, with a low Reynolds number. The results obtained with the lattice Boltzmann method are compared with the ones previously obtained using the finite element method. All the qualitative and quantitative parameters of the two simulations agree.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2004, 8, 1; 5-15
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A new geometrical model for mixing of highly viscous fluids by combining two-blade and helical screw agitators
    Autorzy:
    Hadjeb, A.
    Bouzit, M.
    Kamla, Y.
    Ameur, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/778233.pdf
    Data publikacji:
    2017
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    CFD
    helical agitator
    highly viscous fluid
    stirred tank
    two blade agitator
    Opis:
    Mixing processes are becoming today a huge concern for industrialists in various domains like the pharmaceutical production, oil refining, food industry and manufacture of cosmetic products especially when the processes are related to the mixing of highly viscous products. So the choice of a stirring system for this category of products or fluids must be rigorously examined before use because of the flows which are laminar in the most cases, something that is not good to obtain homogeneous particles or suspensions after the mixing operation. This CFD study allows developing a new geometrical model of mechanical agitator with high performance for mixing of highly viscous fluids. It consists of a combination of two bladed and helical screw agitators. The investigations of the flow structure generated in the vessel are made by using the computer code ANSYS CFX (version 13.0), which allows us to realize and test the effectiveness of the new stirrer on the resulting mixture and power consumption.
    Źródło:
    Polish Journal of Chemical Technology; 2017, 19, 3; 83-91
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Lagrangian Finite Element Treatment of Transient Gravitational Waves in Compressible Viscous Fluids
    Autorzy:
    Staroszczyk, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/241224.pdf
    Data publikacji:
    2007
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    Newtonian viscous fluid
    gravitational wave
    transient problem
    Lagrangian formulation
    finite element method
    Opis:
    In this paper the problem of transient gravitational wave propagation in a viscous compressible fluid is investigated. The problem is formulated in the Lagrangian description and is solved numerically by a finite element method. In computations either fixed in space or moving meshes that follow the material fluid particles are used with the purpose to compare their numerical performance. As illustrations, results of numerical simulations carried out for plane flows in a domain of simple geometry are presented. First, the finite element results are compared with available experimental data for the case of small-amplitude waves in order to validate the numerical model. Then, the problem of large-amplitude transient water wave propagation over a horizontal bottom, involving the wave reflection at a rigid wall, is considered. For the flow parameters typical of a laboratory flume, the evolution of the free-surface elevation and the time variations of the surface displacements at chosen locations are shown for a range of different moving wall amplitudes and excitation times.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2007, 54, 4; 261-284
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On global motion of a compressible barotropic viscous fluid with boundary slip condition
    Autorzy:
    Kobayashi, Takayuki
    Zajączkowski, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1338843.pdf
    Data publikacji:
    1999
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    Hilbert-Besov spaces
    compressible barotropic viscous fluid
    boundary slip condition
    global existence
    Opis:
    Global-in-time existence of solutions for equations of viscous compressible barotropic fluid in a bounded domain Ω ⊂ $ℝ^3$ with the boundary slip condition is proved. The solution is close to an equilibrium solution. The proof is based on the energy method. Moreover, in the $L_2$-approach the result is sharp (the regularity of the solution cannot be decreased) because the velocity belongs to $H^{2+α,1+α/2}(Ω × ℝ_+)$ and the density belongs to $H^{1+α,1/2+α/2}(Ω× ℝ_+)$, α ∈ (1/2,1).
    Źródło:
    Applicationes Mathematicae; 1999, 26, 2; 159-194
    1233-7234
    Pojawia się w:
    Applicationes Mathematicae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On nonstationary motion of a fixed mass of a viscous compressible barotropic fluid bounded by a free boundary
    Autorzy:
    Zadrzyńska, Ewa
    Zajączkowski, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/965957.pdf
    Data publikacji:
    1999
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    free boundary
    compressible viscous barotropic fluid
    global existence
    Źródło:
    Colloquium Mathematicum; 1999, 79, 2; 283-310
    0010-1354
    Pojawia się w:
    Colloquium Mathematicum
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On local motion of a compressible barotropic viscous fluid bounded by a free surface
    Autorzy:
    Zajączkowski, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1361117.pdf
    Data publikacji:
    1992
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    free boundary
    compressible barotropic viscous fluid
    local existence
    anisotropic Sobolev spaces
    surface tension
    Opis:
    We consider the motion of a viscous compressible barotropic fluid in ℝ³ bounded by a free surface which is under constant exterior pressure, both with surface tension and without it. In the first case we prove local existence of solutions in anisotropic Hilbert spaces with noninteger derivatives. In the case without surface tension the anisotropic Sobolev spaces with integration exponent p > 3 are used to omit the coefficients which are increasing functions of 1/T, where T is the existence time.
    Źródło:
    Banach Center Publications; 1992, 27, 2; 511-553
    0137-6934
    Pojawia się w:
    Banach Center Publications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simultaneous chemical reactions effect on dispersion of a solute in peristaltic propulsion of a Newtonian fluid in an inclined channel with wall properties
    Autorzy:
    Dhange, M. Y.
    Sankad, G. C.
    Powiązania:
    https://bibliotekanauki.pl/articles/266133.pdf
    Data publikacji:
    2019
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    dyspersja
    lepki płyn
    napęd perystaltyczny
    dispersion
    inclined channel
    viscous fluid
    peristaltic propulsion
    wall properties
    Opis:
    In this paper, the dispersion of a solute in the peristaltic propulsion of an incompressible and viscous fluid through a permeable medium under the influence of wall properties with simultaneous homogeneous, heterogeneous chemical reactions in an inclined uniform channel has been studied. The issue is studied through conditions of Taylor’s limit and long wavelength hypothesis. The mean effective coefficient of scattering expression is computed and outcomes are interpreted physically through graphs.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2019, 24, 3; 527-538
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On thermosolutal convection in presence of compressible fluid with fine dust
    Autorzy:
    Singh, M.
    Gupta, R. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/955304.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    płyn lepkosprężysty
    ściśliwość
    płyn warstwowy
    Rivlin-Ericksen elastico-viscous fluid
    compressible and fine dust
    Opis:
    A layer of a Rivlin-Ericksen elastico-viscous fluid heated and soluted from below in the presence of compressibility and suspended particles (fine dust) effect is considered. For stationary convection, the Rivlin- Ericksen, elastico-viscous fluid behaves like a Newtonian fluid. The oscillatory modes are introduced due to the presence of a stable solute gradient, suspended particles destabilize the system whereas the stable solute gradient has a stabilizing effect on the system and the effect of compressibility is to postpone the onset of thermosolutal convection. The stable solute gradient and compressibility postpone the onset of convection, whereas the suspended particles hasten the onset of convection. The stable solute gradient introduces oscillatory modes in the systems which were non-existent in its absence.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2014, 19, 1; 133-143
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On a differential inequality for equations of a viscous compressible heat conducting fluid bounded by a free surface
    Autorzy:
    Zadrzyńska, Ewa
    Zajączkowski, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1311522.pdf
    Data publikacji:
    1995
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    free boundary
    compressible viscous heat conducting fluid
    Opis:
    We derive a global differential inequality for solutions of a free boundary problem for a viscous compressible heat conducting fluid. The inequality is essential in proving the global existence of solutions.
    Źródło:
    Annales Polonici Mathematici; 1995, 61, 2; 141-188
    0066-2216
    Pojawia się w:
    Annales Polonici Mathematici
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical Analysis of the Problem of Flow Past a Cylindrical Body Applying the R-Functions Method and The Galerkin Method
    Autorzy:
    Lamtyugova, S.N.
    Sidorov, M. V.
    Powiązania:
    https://bibliotekanauki.pl/articles/410652.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Oddział w Lublinie PAN
    Tematy:
    viscous incompressible fluid
    flow problem
    R-functions method
    Galerkin method
    Opis:
    The article considers the stationary problem of viscous incompressible fluid flow past a cylindrical body. For solving the problem it is proposed a numerical method, based on the joint use of R-functions method and the Galerkin method. The computational experiment has been conducted for the task of flow past square cylinder for different Reynolds numbers.
    Źródło:
    ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2014, 3, 3; 43-50
    2084-5715
    Pojawia się w:
    ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Flow features of thermophoretic MHD viscous fluid flow past a converging channel with heat source and chemical reaction
    Autorzy:
    Kalita, B. K.
    Choudhury, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/2106445.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    magnetohydrodynamika
    płyn lepki
    termoforeza
    liczba Nusselta
    MHD
    viscous fluid
    heat source
    thermophoresis
    Nusselt number
    skin friction
    Opis:
    A boundary layer flow of an electrically conducting viscous fluid past a converging channel in the presence of thermophoresis, heat source, chemical reaction, viscous dissipation and simultaneous heat and mass transfer characteristics is studied in the paper. An external magnetic field of uniform strength is applied transversely to the channel. The similarity solution has been used to transform the partial differential equations that represent the problem into a boundary value problem of coupled ordinary differential equations, which in turn are solved numerically using MATLAB’s built in solver bvp4c. Numerical computations are carried out to solve the problem and graphical illustrations are made to get the physical insight of the same. The convergent channel flow problem of an incompressible electrically conducting viscous fluid in the presence of a magnetic field has a wide range of applicability in different areas of engineering, specially in industrial metal casting and control of molten metal flow.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2021, 26, 3; 72--83
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On a differential inequality for a viscous compressible heat conducting capillary fluid bounded by a free surface
    Autorzy:
    Zadrzyńska, Ewa
    Zajączkowski, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1310796.pdf
    Data publikacji:
    1996
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    free boundary
    compressible viscous heat conducting fluid
    surface tension
    Opis:
    We derive a global differential inequality for solutions of a free boundary problem for a viscous compressible heat concluding capillary fluid. The inequality is essential in proving the global existence of solutions.
    Źródło:
    Annales Polonici Mathematici; 1996-1997, 65, 1; 23-53
    0066-2216
    Pojawia się w:
    Annales Polonici Mathematici
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Unsteady/steady natural convection flow of reactive viscous fluid in a vertical annulus
    Autorzy:
    Jha, B. K.
    Samaila, A. K.
    Ajibade, A. O.
    Powiązania:
    https://bibliotekanauki.pl/articles/265663.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja naturalna
    lepki płyn
    egzotermiczna otulina
    unsteady/steady natural convection flow
    reactive viscous fluid
    exothermic
    open ended vertical annulus
    Opis:
    This paper presents both analytical and numerical analyses of a fully developed unsteady/steady natural convection flow of a reactive viscous fluid in an open ended vertical annulus. Analytical expressions for velocity, temperature, skin-friction and rate of heat transfer are obtained after simplifying and solving the governing differential equations with reasonable approximations. The interesting result found in this study is that an increase in non-dimensional time (t) , increases both temperature and velocity profiles until a steady-state value is attained. Subsequent results obtained by numerical calculations show excellent agreement with analytical results.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2013, 18, 1; 73-83
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mathematical modeling of mudflow dynamics
    Autorzy:
    Gurgenidze, David
    Kipiani, Gela
    Obgadze, Tamaz
    Powiązania:
    https://bibliotekanauki.pl/articles/2065642.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Częstochowska
    Tematy:
    przepływ wody
    przepływ błota
    metoda zmienności
    water-mud flow
    Rvachev-Obgadze variation method
    Geniev-Gogoladze’s baro-viscous fluid
    Opis:
    Despite the on-going efforts of scientists, there are still few scientifically justified mathematical models that give a practical prediction of the origin, dynamics and destructive force of mudflow. Many problems related to the study of mudflows, and especially their dynamics, are not extensively studied due to the complexity of the process. The contributions of Gagoshidze (1949; 1957; 1962; 1970), Natishvili et al. (1976; 1963; 1969), Tevzadze (1971), Beruchashvili et al. (1958; 1969; 1979), Muzaev, Sozanow (1996), Gavardashvili (1986), Fleshman (1978), Vinogradov (1976) towards the study of the hydrology of mudflows deserves attention. In the scientific works of Voinich-Sianozhensky et al. (1984; 1977) and Obgadze (2016; 2019), many different mathematical models have been developed that accurately reflect the dynamics of a mudflow caused by a breaking wave. It should also be noted that many interesting imitation models have been developed by the team of Mikhailov and Chernomorets (1984). In mountainous districts, the first hit of a mudflow is taken on by lattice-type structures offered by Kherkheulidze (1984a; 1984b) that release the flow from fractions of large stones and floating trees. After passing through the lattice-type structures, the mudflow is released from large fractions and turns into a water-mud flow. In order to simulate this flow, a mathematical model based on the baro-viscous fluid model offered by Geniev-Gogoladze (1987; 1985) has been developed, where the averaging formula of Voynich-Sianozhencki is used for the particle density, and for the concentration of the solid phase, the diffusion equation is added to the system dynamics equations. In the given article, for the constructed mathematical model, the exact solution of the one-dimensional flow in the mudflow channel is considered. The problem of stratification of the fluid density under equilibrium conditions is discussed. In the riverbed of the Kurmukhi River, for two-dimensional currents, the problem of flow around the bridge pier with an elliptical cross-section is considered. The Rvachev-Obgadze variation method (1982; 1989a; 1989b) is used to solve the streamlined problem.
    Źródło:
    Budownictwo o Zoptymalizowanym Potencjale Energetycznym; 2021, 10, 1; 27--42
    2299-8535
    2544-963X
    Pojawia się w:
    Budownictwo o Zoptymalizowanym Potencjale Energetycznym
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mathematical modelling of the process of pipeline deformation through which gas-liquid mixtures with aggressive components are transported
    Autorzy:
    Oliynyk, A. P.
    Feshanych, L. I.
    Grygorchuk, G. V.
    Powiązania:
    https://bibliotekanauki.pl/articles/2172155.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    tense state
    pipeline
    viscous fluid flow
    dynamic viscosity
    Navier-Stokes equations
    gas mixture
    rurociąg
    lepkość dynamiczna
    równania Naviera-Stokesa
    mieszanka gazowa
    Opis:
    Purpose Mathematical modelling of the process of deformation of pipeline, transporting gas-liquid mixtures with aggressive components and a comparative analysis of the value of the specified velocity depending on the dynamic viscosity of the multicomponent gas mixture is conducted. Design/methodology/approach A mathematical model of the process of leakage of the transported product due to the loss of tightness of the pipe based on the system of Navier-Stokes equations with boundary conditions with considering the geometry of the leakage zones and the value of the leakage rate is implemented. Findings Models of the process of deformation of the pipeline due to displacements of a certain set of surface points by specifying different types of functions, describing the geometry of deformed sections are constructed. The method of calculating the tensely deformed state based on the data on the movement of surface points by comparing different ways of setting functions, taking into account the actual configuration of sections and axes is improved. The change of flow characteristics in the pipeline when changing the structure of the mix, transported by studying of influence of change of dynamic viscosity is investigated; The method of calculating the rate of leakage of the mixture in case of loss of tightness due to the occurrence of critical stresses in the pipe material is improved. Research limitations/implications Building a model of the deformation process, information about the nature, duration of forces and loads affecting the pipeline is not used. The law of the pipeline movement was constructed having taken into account the deformation of the sections in three directions. The necessity to take wind loads into account, estimating the real tensely deformed state was displayed. Practical implications Using the method of calculating the tensely deformed state based on the data on the movement of surface points by comparing different ways of setting functions, taking into account the actual configuration of sections and axes. Originality/value According to the computational algorithms created on the basis of the specified models, the calculations of the tense state of the pipelines and the flow rate of the mixture depending on its composition were performed. An analysis of the results of calculations - tense intensity and flow rate depending on the dynamic viscosity of the mixture is performed. The influence on the flow parameters - the flow rate of the mixture and the force of hydraulic resistance - changes in the dynamic viscosity of the mixture is analyzed.
    Źródło:
    Journal of Achievements in Materials and Manufacturing Engineering; 2022, 111, 2; 57--63
    1734-8412
    Pojawia się w:
    Journal of Achievements in Materials and Manufacturing Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mathematical models of hydromechanics of multiphase flow with varying mass
    Matematyczne modele hydromechaniki przepływu wielofazowego o zmiennej masie
    Autorzy:
    Mamedov, Gasim A.
    Abbasov, Natiq M.
    Powiązania:
    https://bibliotekanauki.pl/articles/31348256.pdf
    Data publikacji:
    2023
    Wydawca:
    Instytut Nafty i Gazu - Państwowy Instytut Badawczy
    Tematy:
    multiphase flow
    varying mass
    continuum
    phase transition
    viscous fluid
    tension
    pressure
    przepływ wielofazowy
    zmienna masa
    przejście fazowe
    lepka ciecz
    napięcie
    ciśnienie
    Opis:
    The paper discusses the mathematical model of hydromechanics of multiphase flows with varying mass. A multiphase flow is considered a continuum consisting of a set of a large number of different groups of particles. The derivation of motion equations and similarity criteria are given taking into account both the externally attached (or detached) mass and phase transitions within the medium. The equations of mass, momentum and energy transfer for individual phases and the medium as a whole are derived based on fundamental conservation laws. It was demonstrated that in the absence of sources (or flow-offs) of mass, momentum and energy, the known equations of single- and multi-phase flow hydromechanics follow as a special case from the obtained systems of motion equations and similarity criteria. The obtained motion equations are valid for the description of an ingredient of mixture and the medium as a whole, regardless of their physical and mechanical properties. Thermodynamic and rheological state equations, as well as expressions for heat flow, interfacial mass forces phase transitions, and heat exchange between phases can be used to close them. The implemented models make it possible to simulate both the stationary distribution of parameters along the wellbore during production and non-stationary processes that occur, for example, when the pump shaft speed changes during oil production. The developed approaches were implemented in the DataFlow software tool for analysis of the hydrodynamics of multiphase hydrocarbon flows, taking into account heat exchange with the rocks surrounding the well, and phase transitions in the fluid. Using the software package, test calculations were carried out to demonstrate the performance of the proposed and implemented models.
    W artykule omówiono model matematyczny hydromechaniki przepływów wielofazowych o zmiennej masie. Przepływ wielofazowy jest traktowany jako kontinuum składające się ze zbioru dużej liczby różnych grup cząstek. Wprowadzone równania ruchu i kryteria podobieństwa są podane z uwzględnieniem zarówno zewnętrznej dołączonej (lub odłączonej) masy, jak i przejść fazowych wewnątrz ośrodka. Równania transferu masy, pędu i energii dla poszczególnych faz i ośrodka jako całości otrzymano przy użyciu podstawowych praw zachowania. Wykazano, że w przypadku braku źródeł (lub wypływów) masy, pędu i energii, znane równania hydromechaniki przepływu jedno- i wielofazowego wynikają jako szczególny przypadek z otrzymanych układów równań ruchu i kryteriów podobieństwa. Uzyskane równania ruchu mają zastosowanie do opisu składnika mieszaniny i medium jako całości, niezależnie od ich właściwości fizycznych i mechanicznych. Do ich rozwiązania można wykorzystać termodynamiczne i reologiczne równania stanu, a także wyrażenia dotyczące przepływu ciepła, siły międzyfazowych masy, przejść fazowych i wymiany ciepła między fazami. Wdrożone modele umożliwiają symulację zarówno stacjonarnego rozkładu parametrów wzdłuż odwiertu podczas wydobycia, jak i procesów niestacjonarnych, które zachodzą na przykład podczas zmiany prędkości wału pompy w trakcie wydobycia ropy. Opracowane podejścia zostały zaimplementowane w oprogramowaniu DataFlow do analizy hydrodynamiki wielofazowych przepływów węglowodorów, z uwzględnieniem wymiany ciepła ze skałami otaczającymi odwiert oraz przejść fazowych w płynie. Za pomocą pakietu oprogramowania przeprowadzono obliczenia testowe w celu wykazania wydajności proponowanych i wdrożonych modeli.
    Źródło:
    Nafta-Gaz; 2023, 79, 11; 709-715
    0867-8871
    Pojawia się w:
    Nafta-Gaz
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the global existence theorem for a free boundary problem for equations of a viscous compressible heat conducting fluid
    Autorzy:
    Zadrzyńska, Ewa
    Zajączkowski, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1311132.pdf
    Data publikacji:
    1996
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    viscous compressible heat conducting fluid
    global existence
    free boundary problem
    Opis:
    We consider the motion of a viscous compressible heat conducting fluid in ℝ³ bounded by a free surface which is under constant exterior pressure. Assuming that the initial velocity is sufficiently small, the initial density and the initial temperature are close to constants, the external force, the heat sources and the heat flow vanish, we prove the existence of global-in-time solutions which satisfy, at any moment of time, the properties prescribed at the initial moment.
    Źródło:
    Annales Polonici Mathematici; 1996, 63, 3; 199-221
    0066-2216
    Pojawia się w:
    Annales Polonici Mathematici
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The impact of variable fluid properties on natural convection flow past a vertical cone
    Autorzy:
    Srinivasacharya, Darbhasayanam
    Rajender, Bhanoth
    Powiązania:
    https://bibliotekanauki.pl/articles/2202044.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
    Tematy:
    viscous fluid
    vertical isothermal cone
    successive linearization
    Chebyshev collocation method and frequency equation
    ciecz lepka
    pionowy stożek izotermiczny
    linearyzacja sukcesywna
    metoda kolokacji Czebyszewa
    Opis:
    A free convective flow of an incompressible viscous fluid past an isothermal vertical cone is investigated with variable viscosity and variable thermal conductivity. The constant wall temperature (CWT) and constant wall heat flux (CHF) conditions are used as temperature boundary conditions at the surface of the cone. The successive linearization method is applied to linearize the governing nonlinear differential equations of the flow. The numerical solution for the resulting linear equations is attained through the Chebyshev spectral collocation method. The impact of significant parameters on the velocity and temperature, in addition to heat and mass transfer rates, is evaluated and represented graphically for the CWT and CHF situations. The local heat transfer rate decreases, and the coefficient of the skin friction increases with an increase in the viscosity and thermal conductivity parameters for CWT conditions, but the reverse trend is noticed for CHF conditions.
    Źródło:
    Journal of Applied Mathematics and Computational Mechanics; 2022, 21, 4; 73--85
    2299-9965
    Pojawia się w:
    Journal of Applied Mathematics and Computational Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical investigation of vortex wake patterns of laminar flow around two side-by-side cylinders
    Autorzy:
    Nguyen, Van Luc
    Ho, Duy Khanh
    Powiązania:
    https://bibliotekanauki.pl/articles/27309846.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    viscous fluid
    vortex shedding
    vortex wake pattern
    vortex-in-cell method
    two side-by-side cylinders
    lepki płyn
    wir
    wzór budzenia wirowego
    metoda wirowania w komórce
    Opis:
    The laminar flow around two side-by-side circular cylinders was numerically investigated using a vortex-in-cell method combined with a continuous-forcing immersed boundary method. The Reynolds number (Re) of the flow was examined in the range from 40 to 200, and the distance between the cylinders varies from 1.2D to 6D, where D is the cylinder diameter. Simulation results show that the vortex wake is classified into eight patterns, such as single-bluff-body, meandering-motion, steady, deflected-in-one-direction, flip-flopping, anti-phase-synchronization, in-phase-synchronization, and phase-difference-synchronization, significantly depending on the Re, the cylinder distance, and the initial external disturbance effects. The anti-phase-synchronization, in-phase-synchronization, and phase-difference-synchronization vortex patterns can be switched at a low Re after a long time evolution of the flow. In particular, the single-bluff-body and flip-flopping vortex patterns excite the oscillation amplitude of the drag and lift coefficients exerted on the cylinders
    Źródło:
    Archive of Mechanical Engineering; 2022, LXIX, 3; 541--565
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical investigation of the basilar membrane vibration induced by the unsteady fluid flow in the human inner ear
    Autorzy:
    Wahl, Philipp
    Ziegler, Pascal
    Eberhard, Peter
    Powiązania:
    https://bibliotekanauki.pl/articles/1845019.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    human cochlea
    basilar membrane
    unsteady viscous fluid flow
    fluid-structure interaction
    pressure-displacement-based fluid element
    viscous boundary layer
    tonotopy
    auditory threshold
    ludzki ślimak
    membrana podstawna
    niestabilny przepływ cieczy lepkiej
    interakcja płyn-struktura
    element hydrauliczny oparty na ciśnieniu wyporowym
    lepka warstwa graniczna
    tonotopia
    próg słyszalności
    Opis:
    For a deeper understanding of the inner ear dynamics, a Finite-Element model of the human cochlea is developed. To describe the unsteady, viscous creeping flow of the liquid, a pressure-displacement-based Finite-Element formulation is used. This allows one to efficiently compute the basilar membrane vibrations resulting from the fluid-structure interaction leading to hearing nerve stimulation. The results show the formation of a traveling wave on the basilar membrane propagating with decreasing velocity towards the peaking at a frequency dependent position. This tonotopic behavior allows the brain to distinguish between sounds of different frequencies. Additionally, not only the middle ear, but also the transfer behavior of the cochlea contributes to the frequency dependence of the auditory threshold. Furthermore, the fluid velocity and pressure fields show the effect of viscous damping forces and allow us to deeper understand the formation of the pressure difference, responsible to excite the basilar membrane.
    Źródło:
    Archive of Mechanical Engineering; 2020, LXVII, 4; 381-414
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On local existence of solutions of the free boundary problem for an incompressible viscous self-gravitating fluid motion
    Autorzy:
    Mucha, Piotr
    Zajączkowski, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1208168.pdf
    Data publikacji:
    2000
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Tematy:
    anisotropic Sobolev space
    Navier-Stokes equations
    local existence
    sharp regularity
    incompressible viscous barotropic self-gravitating fluid
    Opis:
    The local-in-time existence of solutions of the free boundary problem for an incompressible viscous self-gravitating fluid motion is proved. We show the existence of solutions with lowest possible regularity for this problem such that $u\in W^{2,1}_r(\widetilde{{\mitΩ}}^T)$ with r>3. The existence is proved by the method of successive approximations where the solvability of the Cauchy-Neumann problem for the Stokes system is applied. We have to underline that in the $L_p$-approach the Lagrangian coordinates must be used. We are looking for solutions with lowest possible regularity because this simplifies the proof and decreases the number of compatibility conditions.
    Źródło:
    Applicationes Mathematicae; 2000, 27, 3; 319-333
    1233-7234
    Pojawia się w:
    Applicationes Mathematicae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical simulation of flow and heat transfer in hydromagnetic micropolar fluid between two stretchable disks with viscous dissipation effects
    Autorzy:
    Ali, K.
    Ahmad, S.
    Ashraf, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/279778.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    MHD
    micropolar fluid
    stretchable disk
    viscous dissipation
    couple stress
    heat transfer rate
    Opis:
    A study of magnetohydrodynamic (MHD) flow with viscous dissipation and heat transfer in an electrically conducting laminar steady viscous incompressible micropolar fluid between two infinite uniformly stretching disks is presented. The transformed self similar nonlinear ODEs are first linearized using a quasi linearization method and then solved by employing a combination of a direct and an iterative method. The study may be beneficial to flow and thermal control of polymeric processing.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2016, 54, 2; 633-643
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Obliczenia numeryczne cieczy elektroreologicznej do zastosowania w sterowanym sprzęgle wiskotycznym
    Autorzy:
    Mędrek, Grzegorz
    Osowski, Karol
    Olszak, Artur
    Powiązania:
    https://bibliotekanauki.pl/articles/303499.pdf
    Data publikacji:
    2019
    Wydawca:
    Wydawnictwo Druk-Art
    Tematy:
    sterowane sprzęgło wiskotyczne
    ciecz elektroreologiczna
    obliczenia numerycze
    controlled viscous clutch
    electrorheological fluid
    numerical computation
    Opis:
    We wstępie do artykułu omówiono budowę i sposoby sterowania sprzęgieł wiskotycznych, między innymi poprzez zmianę właściwości cieczy roboczej. Następnie przedstawiono dobór materiałów konstrukcyjnych sterowanego sprzęgła wiskotycznego z cieczą elektroreologiczną (ER). Zasadniczą część artykułu stanowią obliczenia numeryczne cieczy elektroreologicznej oraz sprzęgła. Pokazano przykładowe charakterystyki elektroreologiczne cieczy ERF3-S-I, otrzymane za pomocą procedur obliczeniowych napisanych w programie Turbo Pascal 7 oraz przykładowe wyniki obliczeń sprzęgła tarczowego. Na końcu artykułu zawarto wnioski potwierdzające konieczność modelowania i obliczeń numerycznych właściwości i charakterystyk cieczy elektroreologicznych używanych jako ciecze robocze w sterowanych sprzęgłach wiskotycznych.
    The construction and method of controlling the viscous clutch by changing the properties of working fluid were described in the introduction of the article. Then, the selection of construction materials of the controlled viscous clutch with electrorheological fluid (ER ) was presented. The major part of paper includes numerical calculations of electrorheological fluid and clutch. The exemplary characteristics of electrorheological ERF3-S-I fluid obtained using the calculation procedures presented in Turbo Pascal 7 and the samples of disc clutch were demonstrated. Conclusions regarding the necessity of carrying out the mathematical modelling and numerical calculations of properties as well as characteristics of electrorheological fluids used as working fluid in the controlled viscous clutch were described in the final part of the article.
    Źródło:
    Napędy i Sterowanie; 2019, 21, 10; 68-73
    1507-7764
    Pojawia się w:
    Napędy i Sterowanie
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zastosowanie nowoczesnych cieczy roboczych w chwytakach robotów
    Autorzy:
    Osowski, K.
    Fernández, M. A.
    Olszak, A.
    Huang, C. Y.
    Kęsy, A.
    Chang, J. Y.
    Kęsy, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/305102.pdf
    Data publikacji:
    2018
    Wydawca:
    Wydawnictwo Druk-Art
    Tematy:
    chwytaki
    sprzęgła wiskotyczne
    ciecz elektroreologiczna
    ciecz magnetoreologiczna
    grasper
    viscous coupling
    electro-medical liquid
    magnetorheological fluid
    Opis:
    W artykule omówiono wykorzystanie cieczy o nietypowych właściwościach w chwytakach robotów. Ciecze elektro- i magnetoreologiczne, zmieniające swoje właściwości reologiczne w obecności pola elektrycznego lub magnetycznego, zastosowano jako ciecze robocze sprzęgieł wiskotycznych, wchodzących w skład układu przeniesienia napędu chwytaków. Przedstawiono dwa rozwiązania konstrukcyjne prototypowych chwytaków robotów przemysłowych z takimi sprzęgłami. Rozważono również ciecze luminescencyjne, reagujące na nacisk, pod kątem ich zastosowania w mikroczujnikach siły nacisku szczęk chwytaka.
    The paper discusses the use of modern fluids with untypical properties in robot grippers. The electro- and magnetorheological fluids, changing their rheological properties in the presence of an electric or magnetic field, were used as working fluids of viscous clutches included in the griper drive transmission system. Two design solutions were presented for prototype industrial robot grippers with such clutches. Luminescent pressure-sensitive fluids have also been considered for their use in the micro-sensors for sensing force of the gripper’s jaw.
    Źródło:
    Napędy i Sterowanie; 2018, 20, 3; 100-106
    1507-7764
    Pojawia się w:
    Napędy i Sterowanie
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of dynamic properties attributable to hydraulic lines onto operation of avionic
    Autorzy:
    Ułanowicz, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/247057.pdf
    Data publikacji:
    2011
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    fluid power transmission
    pump delivery
    volume flow rate
    hydrostatic (forcing) pressure
    compressibility effect
    viscous friction effect
    Opis:
    The present paper is dedicated to discuss how dynamic parameters of a hydraulic line intended to transfer hydraulic power from a source of hydraulic power (a hydraulic pump) to an actuating device (a hydraulic motor) can affect operation of an avionic hydraulic drive. Avionic hydraulic drives are operated with fast-varying waveforms of flow intensities and pressures. It is why analysis of most hydraulic drive systems must take account of compressibility of working fluid and elasticity of hydraulic lines. It leads to a wave model for propagation of energy variation down a hydraulic line (a pipe). The paper deals with flow of a compressible liquid via a hydraulic line with flexible walls. Theoretical deliberations were successfully verified by experimental research studies that were carried out on a dedicated test bench, therefore the presented amplitude vs. frequency characteristic curves of the hydraulic line could be obtained from both theoretical considerations and experimental research studied. The experimental research studies were carried out for hydraulic line terminated with a fixed flow restrictor alone and a flow restrictor combined with a hydraulic accumulator as well as for a hydraulic line supplied from a source of constant pressure and terminated with a valve with adjustable flow together with a hydraulic accumulator. The theoretical calculations for the amplitude vs. frequency characteristic curve are based on a model for a hydraulic line with its resistance depending on frequency.
    Źródło:
    Journal of KONES; 2011, 18, 4; 535-542
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of dynamic properties of hydraulic lines for fluid power transmission
    Autorzy:
    Ułanowicz, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/247615.pdf
    Data publikacji:
    2010
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    fluid power transmission
    delivery of a pump
    volume flow rate
    hydrostatic (forcing) pressure
    compressibility effect
    viscous friction effect
    Opis:
    This paper presents the results of a hydraulic line dynamic properties analysis taking into account inertia of the fluid flowing in rigid and flexible lines, the compressibility effect for this fluid and the viscous friction effect. The following are described and analyzed: solution of the wave equation in the form binding four variables: pressure and flow rate at the line input, and pressure and flow rate and the line output; two of the above-mentioned variables should be regarded as independent (input) and the other two as dependent (output), the accuracy comparison of distributed parameters model to lumped parameters model with regard to applicability range in hydraulic systems analysis, pressure value at given installation points as a response to rapid valve closing (transient response) or to valve opening (waterhammer effect). In these considerations the hydraulic line is regarded as a two-port with two inputs and two outputs with a definite transmittance matrix. Main considerations concern the variable resistance model. A general solution is given as a function of the Laplace operator. Introducing appropriate simplifications into the variable resistance model, the constant resistance model and lossless line model is obtained. Also, general solutions for three different lump parameter models are presented. For the lumped parameters lin presents three equivalent models possible, i.e. as: a symmetrical two-port, a two-port with shared resistance and a two-port with capacitance at the output.
    Źródło:
    Journal of KONES; 2010, 17, 3; 467-475
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Scrutinization of Joule heating and viscous dissipation on MHD flow and melting heat transfer over a stretching sheet
    Autorzy:
    Kumar, K. G.
    Gireesha, B. J.
    Manjunatha, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/264626.pdf
    Data publikacji:
    2018
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    metoda numeryczna
    dyssypacja lepkości
    płyn mikropolarny
    Joule heating
    viscous dissipation
    stretching sheet
    micro polar dusty fluid
    numerical method
    Opis:
    The present paper deals with an analysis of the combined effect of Joule heating and viscous dissipation on an MHD boundary layer flow and melting heat transfer of a micro polar fluid over a stretching surface. Governing equations of the problem are transformed into a set of coupled nonlinear ordinary differential equations by applying proper transformations and then they are solved numerically using the RKF-45 method. The method is verified by a comparison with the established results with limiting solution. The influence of the various interesting parameters on the flow and heat transfer is analyzed in detail through plotted graphs.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2018, 23, 2; 429-443
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    MHD effects on non-Newtonian power-law fluid past a continuously moving porous flat plate with heat flux and viscous dissipation
    Autorzy:
    Kishan, N.
    Shashidar Reddy, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/264635.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    wpływ pola magnetycznego
    płyn nienewtonowski
    magnetic field effects
    non-Newtonian fluid
    power-law index
    viscous dissipation and suction/injection
    Opis:
    The problem of a magneto-hydro dynamic flow and heat transfer to a non-Newtonian power-law fluid flow past a continuously moving flat porous plate in the presence of sucion/injection with heat flux by taking into consideration the viscous dissipation is analysed. The non-linear partial differential equations governing the flow and heat transfer are transformed into non-linear ordinary differential equations using appropriate transformations and then solved numerically by an implicit finite difference scheme. The solution is found to be dependent on various governing parameters including the magnetic field parameter M, power-law index n, suction/injection parameter ƒw, Prandtl number Pr and Eckert number Ec. A systematical study is carried out to illustrate the effects of these major parameters on the velocity profiles, temperature profile, skin friction coefficient and rate of heat transfer and the local Nusslet number.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2013, 18, 2; 425-445
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magneto-hydro dynamic flow and heat transfer of non-Newtonian power-law fluid over a non-linear stretching surface with viscous dissipation
    Autorzy:
    Kishan, N.
    Kavitha, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/955131.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    wymiana ciepła
    ciecz lepkosprężysta
    płyn nienewtonowski
    magnetohydrodynamic flow
    power-law fluid
    stretching sheet
    heat source/sink parameter
    viscous dissipation
    Opis:
    A fluid flow and heat transfer analysis of an electrically conducting non-Newtonian power law fluid flowing over a non-linear stretching surface in the presence of a transverse magnetic field taking into consideration viscous dissipation effects is investigated. The stretching velocity, the temperature and the transverse magnetic field are assumed to vary in a power-law with the distance from the origin. The flow is induced due to an infinite elastic sheet which is stretched in its own plane. The governing equations are reduced to non-linear ordinary differential equations by means of similarity transformations. By using quasi-linearization techniques first linearize the non linear momentum equation is linearized and then the coupled ordinary differential equations are solved numerically by an implicit finite difference scheme. The numerical solution is found to be dependent on several governing parameters, including the magnetic field parameter, power-law index, Eckert number, velocity exponent parameter, temperature exponent parameter, modified Prandtl number and heat source/sink parameter. A systematic study is carried out to illustrate the effects of these parameters on the fluid velocity and the temperature distribution in the boundary layer. The results for the local skin-friction coefficient and the local Nusselt number are tabulated and discussed.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2014, 19, 2; 259-273
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stokes flow around slowly rotating concentric previous spheres
    Przepływ stokesowski wokół powolnie wirujących koncentrycznych kul przepuszczalnych
    Autorzy:
    Srivastava, D. K.
    Yadav, R. R.
    Yadav, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/140159.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    rotation of concentric spheres
    fluid sink
    slow viscous flow
    Stokes approximation
    wirowanie kul koncentrycznych
    zlew płynu
    lepki powolny przepływ
    aproksymacja Stokes'a
    Opis:
    In this paper, the problem of concentric pervious spheres carrying a fluid sink at their centre and rotating slowly with different uniform angular velocities Ω1, Ω2 about a diameter has been studied. The analysis reveals that only azimuthal component of velocity exists and the torque, rate of dissipated energy is found analytically in the present situation. The expression of torque on inner sphere rotating slowly with uniform angular velocity Ω1, while outer sphere also rotates slowly with uniform angular velocity Ω2, is evaluated. The special cases like, (i) inner sphere is fixed (i.e. Ω1 = 0), while outer sphere rotates with uniform angular velocity Ω2, (ii) outer sphere is fixed (i.e. Ω2 = 0), while inner sphere rotates with uniform angular velocity Ω1, (iii.) inner sphere rotates with uniform angular velocity Ω1, while outer rotates at infinity with angular velocity Ω2; have been deduced. The corresponding variation of torque with respect to sink parameter has been shown via figures. AMS subject classification – 76 D07.
    W artykule rozważa się problem koncentrycznych kul przepuszczalnych, ze zlewem płynu w centrum, które wirują powoli wokół średnicy z jednostajnymi prędkościami kątowymi Ω1 i Ω2. Analiza wykazała, że istnieje tylko azymutalny składnik prędkości, a moment obrotowy i szybkość rozpraszania energii są w istniejących warunkach wyznaczane analitycznie. Wyprowadzono wyrażenie na moment obrotowy na powierzchni wewnętrznej kuli powolnie wirującej z jednostajną prędkością kątową Ω1, podczas gdy kula zewnętrzna także powolnie wiruje z jednostajną prędkością kątową Ω2. Zbadano także przypadki szczególne, takie jak: (i) kula wewnętrzna jest nieruchoma (tzn. Ω1 = 0), podczas gdy kula zewnętrzna wiruje z jednostajną prędkością kątową Ω2, (ii) kula zewnętrzna jest nieruchoma (tzn. Ω2 = 0), podczas gdy kula wewnętrzna wiruje z jednostajną prędkością kątową Ω1, (iii) kula wewnętrzna wiruje z jednostajną prędkością kątową Ω1, podczas gdy kula zewnętrzna wiruje w nieskończonej odległości z prędkością kątową Ω2. Na wykresach przedstawiono zależności między zmianami momentu obrotowego a parametrami zlewu.
    Źródło:
    Archive of Mechanical Engineering; 2013, LX, 2; 165-184
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    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
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