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    Wyświetlanie 1-33 z 33
    Tytuł:
    Survey of applications of discrete vortex method in civil engineering
    Autorzy:
    Nowicki, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/390713.pdf
    Data publikacji:
    2009
    Wydawca:
    Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
    Tematy:
    discrete vortex method
    Navier-Stokes equation
    Opis:
    This paper includes an introduction to Discrete Vortex Method (DVM) and its comparison with other methods of computer fluid dynamics. In its second part it focuses on the most important applications of DVM from the civil engineering point of view. Some examples known form literature are presented theoretical as well as experimental.
    Źródło:
    Budownictwo i Architektura; 2009, 5, 2; 29-38
    1899-0665
    Pojawia się w:
    Budownictwo i Architektura
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Rationality of solving 3D circulation problems exclusively with the use of the Navier-Stokes equation (Reynolds equation)
    Autorzy:
    Koronowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1986684.pdf
    Data publikacji:
    2002
    Wydawca:
    Politechnika Gdańska
    Tematy:
    3D circulation problems
    vortex theory
    Navier-Stokes equation
    Opis:
    The paper presents problems connected with solving 3D circulation problems. The existence of vortex singularities in the flow behind a body is a characteristic feature of such problems. The vortices influence the velocity and pressure fields in the vicinity of a body. A proposition of rational merging the methods based on the N-S equation together with vortex methods (based on the vorticity equation) is discussed. Such a connection enables accurate and efficient determination of vortex singularities in the flow behind a body.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 1; 217-224
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical simulation of 3D viscous turbomachinery flow with high-resolution ENO scheme and modern turbulence model
    Autorzy:
    Yershov, S. V.
    Rusanov, A. V.
    Powiązania:
    https://bibliotekanauki.pl/articles/1967653.pdf
    Data publikacji:
    2001
    Wydawca:
    Politechnika Gdańska
    Tematy:
    CFD
    computational fluid dynamics CFD
    turbomachinery
    Navier-Stokes equation
    turbulence
    Opis:
    This paper presents the basic principles of construction of numerical models for 3D viscous turbulent flows through multi stage turbomachines. The great attention is given to such properties of the methods as accuracy, linear and non-linear stability, robustness and computational efficiency. It is shown that these properties can be guaranteed if the implicit Godunov’s type ENO scheme is used. A 3D code FLOWER has been developed within this concept. Using the code the numerical results are obtained for flows through high loaded compressor cascades, a turbine stage, a low-pressure multi stage turbine and a centrifugal compressor stage. The results of optimisation of a low-pressure turbine last stage are presented.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 4; 459-476
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Heuristic derivation of Brinkmans seepage equation
    Autorzy:
    Wojnar, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/297997.pdf
    Data publikacji:
    2017
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    porosity
    Darcy’s law
    Stokes’ equation
    successive iterations
    Born’s approximation
    Opis:
    Brinkman’s law is describing the seepage of viscous fluid through a porous medium and is more acurate than the classical Darcy’s law. Namely, Brinkman’s law permits to conform the flow through a porous medium to the free Stokes’ flow. However, Brinkman’s law, similarly as Schro¨dinger’s equation was only devined. Fluid in its motion through a porous solid is interacting at every point with the walls of pores, but the interactions of the fluid particles inside pores are different than the interactions at the walls, and are described by Stokes’ equation. Here, we arrive at Brinkman’s law from Stokes’ flow equation making use of successive iterations, in type of Born’s approximation method, and using Darcy’s law as a zero-th approximation.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2017, 20(4); 359-374
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Laminar flow past the bottom with obstacles - a porous medium approximation
    Autorzy:
    Bielski, Włodzimierz
    Wojnar, Ryszard
    Powiązania:
    https://bibliotekanauki.pl/articles/2104770.pdf
    Data publikacji:
    2022
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    plants
    permeability
    gravity-driven flow
    Darcy-Brinkman’s law
    Stokes equation
    Opis:
    We provide a model of a stationary laminar flow in a channel at the bottom of which plants grow in a dense layer. Since this layer of plants is dense, we treat it as a porous medium and we propose to describe the flow in such a medium by Brinkman’s equation. The flow in the fluid layer located above (infiltrated by water) the layers of plants is described by the Stokes equation. We show that such a model gives results consistent with experimental observations. We indicate also that this new model complements the previously given model in which the benthonic plants were considered as a suspension, so the previous model referred to the channel at the bottom of which the plants grew rare. For high permeability of the porous medium, we arrive at the results obtained for the medium filled with a liquid with a suspension.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 509--520
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fast algorithms for calculations of viscous incompressible flows using the Velocity Correction Method
    Autorzy:
    Kosma, Z.
    Motyl, Przemysław
    Powiązania:
    https://bibliotekanauki.pl/articles/1943235.pdf
    Data publikacji:
    2008
    Wydawca:
    Politechnika Gdańska
    Tematy:
    Navier-Stokes equation
    artificial compressibility
    method of lines
    two grids method
    Opis:
    An artificial compressibility method is designed to simulate stationary two-and threedimensional motions of a viscous incompressible fluid. A standard method of lines approach is applied in this contribution. A partial differential equation system is discretized in space by secondorder finite-difference schemes on uniform computational grids, and the time-variable is preserved as continuous. Initial value problems for systems of ordinary differential equations for pressure and velocity components are computed using the Galerkin-Runge-Kutta method of third order. Some test calculations for laminar flows in square, cubic, triangular and semicircular cavities with one uniform moving wall and double bent channels are reported.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2008, 12, 3-4; 289-301
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fast algorithms for calculations of viscous incompressible flows using the artificial compressibility method
    Autorzy:
    Kosma, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/1943234.pdf
    Data publikacji:
    2008
    Wydawca:
    Politechnika Gdańska
    Tematy:
    Navier-Stokes equation
    velocity correction method
    method of lines
    two grids method
    Opis:
    The velocity correction method is designed to simulate stationary and non-stationary, two- and three-dimensional motions of a viscous incompressible fluid. The basic assumption of this method consists in splitting the velocity and the pressure fields and calculations are performed in two steps. In the first step, a tentative velocity field is determined by simplified equations for momentum conservation. In the second step the Neumann problem for the Poisson equations is solved to obtain the computational pressure, and the velocity components are corrected. A standard method of lines approach and the two grids method are applied in this contribution. Some test calculations for laminar and transitional flows in square and cubic cavities with one moving wall as well as in a backward-facing step are reported.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2008, 12, 3-4; 273-287
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Calculation of viscous incompressible flow around an aerofoil using a modified velocity correction method
    Autorzy:
    Kosma, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/1965150.pdf
    Data publikacji:
    2005
    Wydawca:
    Politechnika Gdańska
    Tematy:
    Navier-Stokes equation
    incompressible viscous flows
    velocity correction method
    flows over aerofoils
    Opis:
    The two-dimensional unsteady motion of viscous incompressible fluid around an aerofoil at a large angle of attack has been computed. A modified velocity correction method splitting the velocity field has been designed to solve this problem. First, a tentative velocity field is determined from the equations of momentum conservation for explicit gradients of computational pressure. Then, the Neumann problem for the Poisson equation is solved to estimate the computational pressure, and velocity components are corrected. Test calculations have been made for the case of flow around the NACA 0012 aerofoil with an incidence of 34 degrees. The domain outside the aerofoil was transformed into a canonical one using conformal mapping. Computations were made on 100×100 and 100×200 grids for Reynolds numbers of Re=400, 600 and 1000. Comparison with numerical and experimental data reported in the literature has shown that the method is suitable for simulating 2D external viscous flows.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 37-52
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Oil pressure distribution in variable height gaps
    Rozklady cisnienia oleju w szczelinach plaskich o zmiennej wysokosci
    Autorzy:
    Zloto, T.
    Kowalski, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/792863.pdf
    Data publikacji:
    2011
    Wydawca:
    Komisja Motoryzacji i Energetyki Rolnictwa
    Tematy:
    variable height gap
    pressure distribution
    hydraulic oil
    hydraulic machine
    Navier-Stokes equation
    Źródło:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2011, 11C
    1641-7739
    Pojawia się w:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Flow behavior in weakly permeable micro-tube with varying viscosity near the wall
    Autorzy:
    Gupta, R. R.
    Kumar, V.
    Chand, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/779656.pdf
    Data publikacji:
    2017
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    hollow-fiber
    micro-tube
    permeation
    algorithm
    variable viscosity
    velocity profile
    equation of motion
    navier-stokes equation
    Opis:
    Weakly permeable micro-tubes are employed in many applications involving heat and/or mass transfer. During these processes, either solute concentration builds up (mass transfer) or steep change in temperature (heat transfer) takes place near the permeable wall causing a change in the viscosity of the fluid. Results of the present work suggest that such change in viscosity leads to a considerable alteration in the flow behavior, and the commonly assumed parabolic velocity profile no longer exists. To solve the problem numerically, the equation of motion was simplified to represent permeation of incompressible, Newtonian fluid with changing viscosity through a micro-tube. Even after considerable simplification, the accuracy of the results was the same as that obtained by previously reported results for some specific cases using rigorous formulation. The algorithm developed in the present work is found to be numerically robust and simple so that it can be easily integrated with other simulations.
    Źródło:
    Polish Journal of Chemical Technology; 2017, 19, 4; 16-21
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Oil leaks intensity in variable-height gaps
    Natężenie przepływu przecieków oleju w szczelinach o zmiennej wysokości
    Autorzy:
    Zloto, T.
    Kowalski, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/792722.pdf
    Data publikacji:
    2013
    Wydawca:
    Komisja Motoryzacji i Energetyki Rolnictwa
    Tematy:
    variable height gap
    hydraulic machine
    Navier-Stokes equation
    hydraulic oil
    oil leakage
    flow intensity
    Źródło:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2013, 13, 2
    1641-7739
    Pojawia się w:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A comparative study on translational diffusion coefficient for some mammalian serum albumins
    Porównanie współczynnika dyfuzji translacyjnej dla albumin surowicy kilku ssaków
    Autorzy:
    Monkos, Karol
    Powiązania:
    https://bibliotekanauki.pl/articles/1039603.pdf
    Data publikacji:
    2010
    Wydawca:
    Śląski Uniwersytet Medyczny w Katowicach
    Tematy:
    viscosity
    stokes-einstein equation
    serum albumin
    translational diffusion coefficient
    Opis:
    BACKGROUND The aim of the present paper is investigation of the volume fraction dependence of the translational diffusion coefficient for some mammalian serum albumins in aqueous solutions. MATERIAL AND METHODS The viscosity of bovine, equine, ovine and rabbit serum albumin aqueous solutions was measured at temperatures ranging from 5oC to 45oC and in a wide range of concentrations. The measurements were performed with an Ubbelohde-type capillary microviscometer. RESULTS Translational diffusion coefficient at infinitely dilute solutions Do(T) can be calculated from generalized Stokes-Einstein equation if the hydrodynamic radius of albumin is known. It gives Do(T) in the range from 3.5×10-11 m2 /s (at 5oC) to 10.2 10-11 m2 /s (at 45oC) for bovine serum albumin, from 3.59×10-11 m2 /s (at 5oC) to 10.4 10-11 m2 /s (at 45oC) for equine serum albumin, from 3.42×10-11 m2 /s (at 5oC) to 9.92×10-11 m2 /s (at 45oC) for ovine serum albumin, and from 3.36×10-11 m2 /s (at 5oC) to 9.74×10-11 m2 /s (at 45oC) for rabbit serum albumin. Translational diffusion coefficient for higher concentrations D(T,φ) can be obtained from the relation: D(T,φ) = Do(T)Ηo(T)/Η(T,φ), where φ denotes volume fraction and Ηo(T) and Η(T,φ) are viscosities of water and solution, respectively, at temperature T. CONCLUSIONS The obtained results show that the translational diffusion coefficient decreases linearly with increasing volume fraction, when φ does not exceed the value of about 0.1. The dependence of the translational diffusion coefficient on volume fraction in a broader range of φ, i.e. from dilute to concentrated solutions, is nonlinear and can be described by a stretched exponential function.
    WSTĘP Celem niniejszej pracy jest zbadanie zależności współczynnika dyfuzji translacyjnej od ułamka objętościowego dla albumin surowicy kilku ssaków w roztworach wodnych. MATERIAŁ I METODY Lepkość wodnych roztworów albuminy surowicy wołowej, końskiej, owczej i króliczej zmierzono w zakresie temperatur od 5oC do 45oC i w szerokim zakresie stężeń. Pomiary wykonano przy pomocy kapilarnego mikrowiskozymetru typu Ubbelohde’a. WYNIKI Współczynnik dyfuzji translacyjnej dla roztworów rozcieńczonych Do(T) można obliczyć z uogólnionego równania Stokesa-Einsteina, jeżeli znany jest promień hydrodynamiczny albuminy. Daje to Do(T) w zakresie od 3.5×10-11 m2 /s (w 5oC) do 10.2×10-11 m2 /s (w 45oC) dla albuminy surowicy wołowej, od 3.59×10-11 m2 /s (w 5oC) do 10.4×10-11 m2 /s (w 45oC) dla albuminy surowicy końskiej, od 3.42×10-11 m2 /s (w 5oC) do 9.92×10-11 m2 /s (w 45oC) dla albuminy surowicy owczej i od 3.36×10-11 m2 /s (w 5oC) do 9.74×10-11 m2 /s (w 45oC) dla albuminy surowicy króliczej. Współczynnik dyfuzji translacyjnej dla wyższych stężeń D(T,φ) można otrzymać z relacji: D(T,φ) = Do(T)Ηo(T)/Η(T,φ), w której φ oznacza ułamek objętościowy a Ηo(T) i Η(T,φ) są, odpowiednio, lepkością wody i roztworu w temperaturze T. WNIOSKI Otrzymane wyniki pokazują, że współczynnik dyfuzji translacyjnej maleje liniowo wraz ze wzrostem ułamka objętościowego, jeżeli φ nie przekracza wartości około 0.1. Zależność współczynnika dyfuzji translacyjnej od ułamka objętościowego w szerszym zakresie φ , tzn. dla roztworów od rozcieńczonych do stężonych, jest nieliniowa i można ją opisać rozciągniętą funkcją wykładniczą.
    Źródło:
    Annales Academiae Medicae Silesiensis; 2010, 64, 5-6; 43-53
    1734-025X
    Pojawia się w:
    Annales Academiae Medicae Silesiensis
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The well-posedness of a swimming model in the 3-D incompressible fluid governed by the nonstationary Stokes equation
    Autorzy:
    Khapalov, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/330536.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    swimming model
    coupled PDE/ODE system
    nonstationary Stokes equation
    sprzężony system PDE/ODE
    równanie Stokesa
    Opis:
    We introduce and investigate the well-posedness of a model describing the self-propelled motion of a small abstract swimmer in the 3-D incompressible fluid governed by the nonstationary Stokes equation, typically associated with low Reynolds numbers. It is assumed that the swimmer’s body consists of finitely many subsequently connected parts, identified with the fluid they occupy, linked by rotational and elastic Hooke forces. Models like this are of interest in biological and engineering applications dealing with the study and design of propulsion systems in fluids.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2013, 23, 2; 277-290
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Addendum to “The well-posedness of a swimming model in the 3-D incompressible fluid governed by the nonstationary Stokes equation”
    Autorzy:
    Khapalov, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/330456.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    swimming model
    coupled PDE/ODE system
    nonstationary Stokes equation
    sprzężony system PDE/ODE
    równanie Stokesa
    Opis:
    In this addendum we address some unintentional omission in the description of the swimming model in our recent paper (Khapalov, 2013).
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2013, 23, 4; 905-906
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical investigation of flow in mixed-flow pump with volute
    Autorzy:
    Sedlar, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1967635.pdf
    Data publikacji:
    2001
    Wydawca:
    Politechnika Gdańska
    Tematy:
    CFD
    computational fluid dynamics CFD
    flow separation
    cavitation
    Navier-Stokes equation
    unsteady phenomena
    mixed-flow pump
    volute
    Opis:
    The work considers the modelling of flow in a complete mixed-flow pump with volute, including tip leakage flows, using both quasi-steady and true transient models of rotor/stator interaction. The CFX-TASCflow CFD package from AEA Technology is applied to calculate flows for a wide range of flow rates from about 0.2 to 1.4 Q/sub 0pt/. Fairly detailed flow structures have been predicted based on the flow rates, especially impeller inlet recirculation and separation on the suction side of the blades for suboptimal rates of flow, as well as strong secondary flows and separation in the volute for off-design conditions. The rotor/stator interaction influence on flow phenomena both in the impeller and volute have been investigated with very interesting results, providing good insight into the dynamics of flow close to the volute tongue. Based on the computational results, pump performance curves (Q-H, Q- eta /sub h/ and Q-P, eta /sub h/ being the hydraulic efficiency) have been obtained. The data from this numerical investigation have been used to improve the inlet part of the impeller blades, especially close to the tip. The geometry modifications have resulted in reduced cavitation in the impeller as well as noise at suboptimal rates of flow.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 4; 595-602
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Method of lines for the incompressible Navier-Stokes equations in the stream-function formulation
    Autorzy:
    Kosma, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/1965151.pdf
    Data publikacji:
    2005
    Wydawca:
    Politechnika Gdańska
    Tematy:
    Navier-Stokes equation
    stream-function formulation
    method of lines
    compact schemes
    driven cavity
    backward-facing step flow
    Opis:
    The aim of this paper is to simulate the laminar motion of viscous incompressible fluid and the transition between the laminar and the turbulent state in simply connected domains. The developed numerical algorithms are based on the solution of an initial-boundary value problem for the full incompressible Navier-Stokes equations, written in the form of a fourth-order equation for the stream function. The spatial derivatives and the boundary conditions are discretized on uniform grids by means of sixth-order compact schemes together with fourth-order finite-difference formulas, while the continuity of the time variable is preserved. The resulting system of ordinary differential equations has been integrated using the backward-differentiation predictor-corrector method. The efficiency of the numerical algorithms is demonstrated by solving two problems of viscous liquid plane flows in a square driven cavity and a backward-facing step. Calculations for the cavity flow configuration have been obtained for Reynolds numbers ranging from Re=100 to Re=30000 on uniform 50×50 and 100×100 grids. Calculations for the backward-facing step have been made for Re ≤ 3000 with channel lengths, L, within the range 10-30, on 30L×30 uniform grids. The computed stream-function contours and velocity fields have been compared with numerical results reported in the literature.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 17-35
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of CFD for analysis of the ship and propeller flow
    Autorzy:
    Bugalski, T. J.
    Szantyr, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1953974.pdf
    Data publikacji:
    1998
    Wydawca:
    Politechnika Gdańska
    Tematy:
    computational fluid dynamics CFD
    CFD
    propeller flow
    ships
    Navier-Stokes equation
    free surface
    propeller operation
    PANSHIP computer system
    Opis:
    The paper describes the computer system PANSHIP for analysis of flow around the ship hull moving with constant velocity in calm water, including the effects of free surface and propeller operation. This system calculates the potential flow using the discrete distribution of Rankine sources on the hull. Viscous flow is computed using the integral method in the bow section and Reynolds averaged Navier Stokes equation (RANS) in the stern section of the ship hull. Results of this analysis may be directly used in ship hull design and they may also serve as input for calculation of the unsteady flow phenomena accompanying propeller operation in the non-uniform velocity field generated by the hull. PANSHIP has been verified experimentally and it forms a useful tool available for ship designers and for marine hydrodynamicists.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1998, 2, 2; 349-356
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An analysis of pressure distribution in water and water emulsion in a front gap of a hydrostatic bearing
    Analiza rozkładu ciśnienia wody i emulsji wodnej w szczelinie czołowej łożyska hydrostatycznego
    Autorzy:
    Kowalski, K.
    Zloto, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/792293.pdf
    Data publikacji:
    2014
    Wydawca:
    Komisja Motoryzacji i Energetyki Rolnictwa
    Tematy:
    pressure distribution
    water
    water emulsion
    variable height gap
    hydrostatic thrust bearing
    Navier-Stokes equation
    geometrical parameter
    exploitation condition
    Źródło:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2014, 14, 4
    1641-7739
    Pojawia się w:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Pressure distributions in oil film in the front gap of a hydrostatic thrust bearing
    Rozklady cisnienia w filmie olejowym szczeliny czolowej lozyska hydrostatycznego wzdluznego
    Autorzy:
    Zloto, T.
    Kowalski, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/793238.pdf
    Data publikacji:
    2012
    Wydawca:
    Komisja Motoryzacji i Energetyki Rolnictwa
    Tematy:
    hydrostatic thrust bearing
    pressure distribution
    oil film
    Navier-Stokes equation
    geometrical dimension
    exploitation parameter
    front gap
    geometrical parameter
    Źródło:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2012, 12, 2
    1641-7739
    Pojawia się w:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Novel method of physical modes generation for reduced order flow control-oriented models
    Autorzy:
    Morzyński, M.
    Nowak, M.
    Stankiewicz, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/127922.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    Navier-Stokes equation
    eigenmodes
    Reduced Order Modelling
    flow control
    równanie Naviera-Stokesa
    postać drgań własnych
    modelowanie zredukowanego rzędu
    kontrola przepływu
    Opis:
    Physical flow modes are of particular interest for Reduced Order Flow Control-Oriented Models. Computation of physical modes as the eigensolution of linearized Navier-Stokes equations is a cumbersome and difficult task, especially for large, 3D problems. Instead we propose the solution of Navier-Stokes equation in the frequency domain and investigation of the system response to local or global perturbation. The flow variables are perturbed around steady basic state and the system response is used to construct mode basis suitable for ROMs.
    Źródło:
    Vibrations in Physical Systems; 2014, 26; 189-194
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Oil pressure distribution in conical ring gaps
    Rozklady cisnienia oleju w szczelinach pierscieniowych stozkowych
    Autorzy:
    Zloto, T.
    Kowalski, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/793712.pdf
    Data publikacji:
    2012
    Wydawca:
    Komisja Motoryzacji i Energetyki Rolnictwa
    Tematy:
    piston-cylinder pump
    pressure distribution
    oil pressure distribution
    conical ring gap
    piston pump
    hydraulic motor
    Navier-Stokes equation
    viscosity
    hydraulic system
    computational model
    Źródło:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2012, 12, 2
    1641-7739
    Pojawia się w:
    Teka Komisji Motoryzacji i Energetyki Rolnictwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Studies of a mixing process induced by a rotating magnetic field with the application of magnetic particles
    Autorzy:
    Rakoczy, Rafał
    Kordas, Marian
    Markowska-Szczupak, Agata
    Konopacki, Maciej
    Augustyniak, Adrian
    Jabłońska, Joanna
    Paszkiewicz, Oliwia
    Dubrowska, Kamila
    Story, Grzegorz
    Story, Anna
    Ziętarska, Katarzyna
    Sołoducha, Dawid
    Borowski, Tomasz
    Roszak, Marta
    Grygorcewicz, Bartłomiej
    Dołęgowska, Barbara
    Powiązania:
    https://bibliotekanauki.pl/articles/2086782.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    mixing process
    alternating magnetic field
    magnetic particles
    mixing time
    Navier–Stokes equation
    proces mieszania
    zmienne pole magnetyczne
    cząstki magnetyczne
    czas mieszania
    równanie Naviera-Stokesa
    Opis:
    We demonstrate in this study that a rotating magnetic field (RMF) and spinning magnetic particles using this kind of magnetic field give rise to a motion mechanism capable of triggering mixing effect in liquids. In this experimental work two mixing mechanisms were used, magnetohydrodynamics due to the Lorentz force and mixing due to magnetic particles under the action of RMF, acted upon by the Kelvin force. To evidence these mechanisms, we report mixing time measured during the neutralization process (weak acid-strong base) under the action of RMF with and without magnetic particles. The efficiency of the mixing process was enhanced by a maximum of 6.5% and 12.8% owing to the application of RMF and the synergistic effect of magnetic field and magnetic particles, respectively
    Źródło:
    Chemical and Process Engineering; 2021, 42, 2; 157--172
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stabilization of a fluid structure interaction with nonlinear damping
    Autorzy:
    Lasiecka, I.
    Lu, Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/206598.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    fluid structure interaction
    interface
    Navier-Stokes equation
    system of elasticity
    feedback boundary control
    strong stability
    uniform stability
    optimal control
    passive damping
    active damping
    dynamic and static damping
    Opis:
    Asymptotic stability of finite energy solutions to a fluid-structure interaction with a static interface in a bounded domain Ω ∈ Rn, n = 2 is considered. It is shown that the undamped model subject to ”partial flatness” geometric condition on the in- terface produces solutions whose energy converges strongly to zero; while with a stress type feedback control applied on the interface of the structure, the model produces solutions whose energy is exponentially stable. An addition of a static damping on the interface produces solutions whose full norm in the phase space is exponentially stable. Without a static damping an interesting phenomenon occurs that steady state solutions (equilibria) might generate genuinely growing in time solutions. This is purely nonlinear phenomenon captured by newly developed techniques amenable to handle instability of steady state solutions arising from nonlinearity.
    Źródło:
    Control and Cybernetics; 2013, 42, 1; 155-181
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dusty time fractional MHD flow of a Newtonian fluid through a cylindrical tube with a non-Darcian porous medium
    Autorzy:
    Imo-Mani-Singha, H.
    Sengupta, Sanjib
    Powiązania:
    https://bibliotekanauki.pl/articles/1839832.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
    Tematy:
    time-fractional order Navier-Stokes equation
    Laplace decomposition method
    LDM
    Magnetohydrodynamics
    MHD
    dusty flow
    non-Darcy porous medium
    ciecz newtonowska
    przepływ cieczy nienewtonowskiej
    Laplace Decomposition Method
    magnetohydrodynamika
    Opis:
    In this paper, time fractional flow of a Newtonian fluid through a uniform cylindrical tube with a non-Darcy porous medium in the presence of dust particles under the application of a uniform magnetic field along the meridian axis is discussed. The implication of time fractional order differential equations in flow problems and some benefits of fractional order differential equations are highlighted. The Laplace Decomposition Method (LDM) is used to obtain an approximate solution to the proposed problem. The impact of fractional order and integer order of the differential equations and also the effects of some important parameters on the flow system are shown in the forms of graphs and a table. The convergence test of the solution is done. It has been observed that the fractional order differential equation reveals more things like the decrease in dust particle velocity due to the increase in magnetic field for fractional order derivatives, whereas, no noticeable change in dust particle velocity due to the change in magnetic field for integer order derivatives are observed. Also, it is observed that an increase in a fractional order derivative decrease the fluid as well as the dust particle velocities. The skin friction at the walls of the tube are also highlighted.
    Źródło:
    Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 4; 101-114
    2299-9965
    Pojawia się w:
    Journal of Applied Mathematics and Computational Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical simulation of 3D flow in axial turbomachines
    Autorzy:
    Yershov, S.
    Rusanov, A. V.
    Gardzielewicz, A.
    Lampart, P.
    Świrdyczuk, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1953978.pdf
    Data publikacji:
    1998
    Wydawca:
    Politechnika Gdańska
    Tematy:
    numerical simulation
    axial turbomachines
    3D flow
    3D viscous compressible flow
    Navier-Stokes equation
    ENO reconstruction
    computational efficiency
    computational fluid dynamics CFD
    Godunov-type upwind differencing
    Opis:
    The paper is intended to describe a method for the calculation of 3D viscous compressible (subsonic or supersonic) flow in axial turbomachines described in the form of thin-layer Reynolds-averaged Navier-Stokes equations. The method draws on Godunov-type upwind differencing and ENO reconstruction suggested by Harten (1987), so as to assure monotonicity preservation and high accuracy of computational results. The computational efficiency is achieved thanks to the implementation of a simplified H-type multi-grid approach and delta -form implicit step. Turbulent effects are simulated with the help of a modified algebraic model of Baldwin-Lomax (1978). This method was at the foundation of a computer code-a complex software package to calculate 3D flow in multi-stage turbomachines that allows us to obtain local characteristics, like temperature, pressure, density or velocity distributions, as well as global characteristics, such as flow rates, stage reaction, flow efficiency for the considered turbine/compressor stage. The paper also gives selected results of computation of a number of turbomachinery cascades, showing that these results agree reasonably well with the available experimental data.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1998, 2, 2; 319-347
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dusty time fractional MHD flow of a Newtonian fluid through a cylindrical tube with a non-Darcian porous medium
    Autorzy:
    Imo-Mani-Singha, H.
    Sengupta, Sanjib
    Powiązania:
    https://bibliotekanauki.pl/articles/1839728.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
    Tematy:
    time-fractional order Navier-Stokes equation
    Laplace decomposition method
    LDM
    Magnetohydrodynamics
    MHD
    dusty flow
    non-Darcy porous medium
    ciecz newtonowska
    przepływ cieczy nienewtonowskiej
    Laplace Decomposition Method
    magnetohydrodynamika
    Opis:
    In this paper, time fractional flow of a Newtonian fluid through a uniform cylindrical tube with a non-Darcy porous medium in the presence of dust particles under the application of a uniform magnetic field along the meridian axis is discussed. The implication of time fractional order differential equations in flow problems and some benefits of fractional order differential equations are highlighted. The Laplace Decomposition Method (LDM) is used to obtain an approximate solution to the proposed problem. The impact of fractional order and integer order of the differential equations and also the effects of some important parameters on the flow system are shown in the forms of graphs and a table. The convergence test of the solution is done. It has been observed that the fractional order differential equation reveals more things like the decrease in dust particle velocity due to the increase in magnetic field for fractional order derivatives, whereas, no noticeable change in dust particle velocity due to the change in magnetic field for integer order derivatives are observed. Also, it is observed that an increase in a fractional order derivative decrease the fluid as well as the dust particle velocities. The skin friction at the walls of the tube are also highlighted.
    Źródło:
    Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 4; 101-114
    2299-9965
    Pojawia się w:
    Journal of Applied Mathematics and Computational Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of a near wall model to Navier-Stokes equations with nonlinear time-relaxation model
    Autorzy:
    İhan, Özgül
    Powiązania:
    https://bibliotekanauki.pl/articles/2175530.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
    Tematy:
    boundary layers
    laminar
    near wall models
    NWM
    Navier-Stokes equation with nonlinear time-relaxation model
    NSE-NTR
    warstwy graniczne
    równanie Naviera-Stokesa z nieliniowym modelem relaksacji w czasie
    Opis:
    It is difficult and essential to determine appropriate boundary conditions for the flow averages because they depend on the behavior of the unknown flow near the wall. Large-eddy simulation (LES) is one of the promising approaches. LES estimates local spatial averages ū of the velocity u of the fluid. The main problem is modeling near-wall turbulence in complex geometries. Inspired by the works of Navier and Maxwell, the boundary conditions are developed on the wall. In this study, the appropriate friction coefficient for 2-D laminar flows is computed, and existing boundary layer theories are used to improve numerical boundary conditions for flow averages. The slip with friction and penetration with resistance boundary conditions are considered. Numerical tests on two-dimensional channel flow across a step using this boundary condition on the top and bottom wall and the step are performed.
    Źródło:
    Journal of Applied Mathematics and Computational Mechanics; 2022, 21, 2; 39--50
    2299-9965
    Pojawia się w:
    Journal of Applied Mathematics and Computational Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Temperature and concentration dependence of translational diffusion coefficient for human serum albumin in aqueous solutions at different pH
    Zależność współczynnika dyfuzji translacyjnej od temperatury i stężenia dla albuminy surowicy ludzkiej w roztworach wodnych przy różnych wartościach pH
    Autorzy:
    Monkos, Karol
    Powiązania:
    https://bibliotekanauki.pl/articles/1034868.pdf
    Data publikacji:
    2013
    Wydawca:
    Śląski Uniwersytet Medyczny w Katowicach
    Tematy:
    translational diffusion coefficient
    viscosity
    stokes-einstein equation
    human serum albumin
    współczynnik dyfuzji translacyjnej
    lepkość
    równanie stokesa-einsteina
    albumina surowicy ludzkie
    Opis:
    B A C K G R O U N D The aim of the present paper is to investigate the temperature and concentration dependence of the translational diffusion coefficient for human serum albumin in aqueous solutions at neutral pH and at the isoelectric point. M A T E R I A L A N D M E T H O D S The viscosity of human serum albumin aqueous solutions at pH 4.7 and 7.0 was measured at temperatures ranging from 5oC to 45oC and in a wide range of con-centrations. The measurements were performed with an Ubbelohde-type capillary microviscometer. R E S U L T S The translational diffusion coefficient of a protein in infinitely dilute solutions Do(T) can be calculated from the generalized Stokes-Einstein equation if the hydrodynamic radius of the studied protein is known. For hydrated human serum albumin, this equation gives Do(T) in the range of 3.45 x 10-11 m2/s (at 5oC) to 10.0 x 10-11 m2/s (at 45oC). The translational diffusion coefficient for higher concentrations of D(T,F) can be obtained from the relation: D(T,F) = Do(T)ho(T)/h(T,F), where F denotes the volume fraction and ho(T) and h(T, F) are the viscosities of water and the solution at temperature T, respectively. C O N C L U S I O N S The translational diffusion coefficient of human serum albumin in solutions both at pH 4.7 and 7.0 decreases linearly with increasing volume fraction, when does not exceed the value of about 0.11. The dependence of the translational diffusion coefficient on volume fraction in the whole measured range of is non-linear and can be described by a stretched exponential function. The scaling parameters in this function are different at different values of pH. The dependence of the translational diffusion coefficient on temperature, in turn, can be described by the three-parameter Vogel-Tammann-Fulcher’s equation.
    W S T Ę P Celem niniejszej pracy jest zbadanie zależności współczynnika dyfuzji translacyjnej od temperatury i ułamka objętościowego dla albuminy surowicy ludzkiej w roztworach wodnych przy neutralnym pH oraz w punkcie izoelektrycznym. M A T E R I A Ł I M E T O D Y Lepkość wodnych roztworów albuminy surowicy ludzkie j przy pH 4,7 i 7,0 zmierzono w zakresie temperatur 5–45 o C i w szerokim zakresie stężeń. Pomiary wykonano za pomocą kapilarnego mikrowiskozymetru typu Ubbe-lohde’a. W Y N I K I Współczynnik dyfuzji translacyjnej białka dla roztworów rozcieńczonych D o (T) można obliczyć z uogólnionego równania Stokesa-Einsteina, jeżeli znany jest promień hydrodynamiczny badanego białka. Dla uwodnionej albuminy surowicy ludzkiej równanie to daje D o (T) w zakresie od 3,45 ¥ 10 -11 m 2 /s (w 5 o C) do 10,0 ¥ 10 -11 m 2 /s (w 45 o C). Współczynnik dyfuzji translacyjnej dla wyższych stężeń D(T, F ) można otrzymać z relacji: D(T, F ) = D o (T) h o (T)/ h (T, F ), w której F oznacza ułamek objętościowy a h o (T) i h (T, F ) to lepkości, odpowiednio, wody i roztworu w temperaturze T. W N I O S K I Współczynnik dyfuzji translacyjnej albuminy surowicy ludzkiej w roztworach wodnych zarówno przy pH 4,7 jak i 7,0 maleje liniowo wraz ze wzrostem ułamka objętościowego, jeżeli F nie przekracza wartości około 0,11. Zależność współczynnika dyfuzji translacyjnej od ułamka objętościowego w całym mierzonym zakresie F jest nieliniowa i można ją opisać rozciągniętą funkcją wykładniczą. Parametry skalowania w tej funkcji są różne przy różnych wartościach pH. Z kolei zależność współczynnika dyfuzji translacyjnej od temperatury może być opisana przez trójparametryczne równanie Vogela-Tammanna-Fulchera.
    Źródło:
    Annales Academiae Medicae Silesiensis; 2013, 67, 3; 184-193
    1734-025X
    Pojawia się w:
    Annales Academiae Medicae Silesiensis
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fourth order nonlinear evolution equation for interfacial gravity waves in the presence of air flowing over water and a basic current shear
    Autorzy:
    Majumder, D. P.
    Dhar, A. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/265668.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    nonlinear evolution equation
    basic current shear
    Stokes gravity wave
    równania nieliniowe
    przepływy Stokes'a
    grawitacja
    Opis:
    A fourth order nonlinear evolution equation, which is a good starting point for the study of nonlinear water waves as first pointed out by Dysthe (1979) is derived for gravity waves propagating at the interface of two superposed fluids of infinite depth in the presence of air flowing over water and a basic current shear. A stability analysis is then made for a uniform Stokes gravity wave train. Graphs are plotted for the maximum growth rate of instability and for wave number at marginal stability against wave steepness for different values of air flow velocity and basic current shears. Significant deviations are noticed from the results obtained from the third order evolution equation, which is the nonlinear Schrödinger equation.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2015, 20, 3; 517-530
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Symulacja linii prądu w przepływach Stokesa metodą brzegowych równań całkowych
    Simulation of the streamlines of Stokes flow using Boundary Integral Equation Method
    Autorzy:
    Teleszewski, T. J.
    Rynkowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/404284.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Symulacji Komputerowej
    Tematy:
    linie prądu
    symulacja
    przepływy Stokes'a
    metoda brzegowych równań całkowych
    streamlines
    simulation
    Stokes flow
    boundary integral equation method
    Opis:
    Opracowanie zawiera zaproponowany algorytm wyznaczania linii prądu w przepływach Stokes’a metodą brzegowych równań całkowych. W celu walidacji metody elementów brzegowych porównano rozwiązania metodą brzegowych równań całkowych ze znanym eksperymentem. Przedstawiony algorytm może być wykorzystany do wyznaczania linii prądu w płaskich przepływach Stokes’a w różnych dziedzinach techniki. W prezentowanej pracy przedstawiono przykładowe graficzne rezultaty obliczeń dla wybranych przykładów, dla których nie są znane rozwiązania analityczne. Algorytm został zaimplementowany w autorskim programie obliczeniowym napisanym w języku Fortran.
    In this article it has been introduced the way to calculate streamlines of Stokes flow using Boundary Integral Equation Method. The algorithm was verified using a known experiment S. Taneda. The computer program was written in Fortran programming language. The algorithm BEM enables very effective solving of test and practical problems in engineering and can be alternative to mesh methods like Finite Difference Method, Finite Volume Method or Finite Element Method. A numerical examples were presented.
    Źródło:
    Symulacja w Badaniach i Rozwoju; 2011, 2, 1; 47-54
    2081-6154
    Pojawia się w:
    Symulacja w Badaniach i Rozwoju
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Alien derivatives of the WKB solutions of the gauss hypergeometric differential equation with a large parameter
    Autorzy:
    Tanda, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/255675.pdf
    Data publikacji:
    2015
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    hypergeometric differential equation
    WKB solution
    Voros coefficient
    alien derivative
    Stokes curve
    fixed singularity
    Opis:
    We compute alien derivatives of the WKB solutions of the Gauss hypergeometric differential equation with a large parameter and discuss the singularity structures of the Borel transforms of the WKB solution expressed in terms of its alien derivatives.
    Źródło:
    Opuscula Mathematica; 2015, 35, 5; 803-823
    1232-9274
    2300-6919
    Pojawia się w:
    Opuscula Mathematica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On free convection heat transfer from vertical plate - proposition of a new model
    Autorzy:
    Leble, S.
    Lewandowski, W. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1938587.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Gdańska
    Tematy:
    Navier-Stokes equations
    Fourier-Kirchhoff equation
    free convective heat transfer
    analytical solution
    sothermal surface
    boundary layer
    vertical plate
    Opis:
    The free convection heat transfer from an isothermal vertical plate in open space is investigated theoretically. In contrast to conventional approaches we use neither boundary layer nor self-similarity concepts. We base on expansion of the fields of velocity and temperature in a Taylor Series in x coordinate with coefficients being functions of the vertical coordinate (y). In the minimal version of the theory we restrict ourselves by cubic approximation for both functions. The Navier-Stokes and Fourier-Kirchhoff equations that describe the phenomenon give links between coefficient functions of y that after exclusion leads to the ordinary differential equation of forth order (of the Mittag-Leffleur type). Such construction implies four boundary conditions for a solution of this equation while the links between the coefficients need two extra conditions. All the conditions are chosen on the basis of the experience usual for free convection. The choice allows us to express all the theory parameters as functions of the Rayleigh number and the temperature difference. To support the conformity of the theory we derive the Nusselt-Rayleigh numbers relation that has the traditional form. The solution in the form of velocity and temperature profiles is evaluated and illustrated for air by examples of plots of data.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2016, 20, 2; 249-265
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modeling of heat transfer and fluid flow in a rectangular channel with an obstacle
    Autorzy:
    Stryczyński, Mikołaj
    Majchrzak, Ewa
    Powiązania:
    https://bibliotekanauki.pl/articles/1839780.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
    Tematy:
    channel with an obstacle
    Fourier-Kirchhoff equation
    Navier-Stokes equations
    finite difference method
    równanie Fouriera-Kirchhoffa
    równania Naviera-Stokesa
    metoda różnic skończonych
    Opis:
    Heat transfer and fluid flow in the rectangular channel with an obstacle are considered. The problem is described by the Fourier-Kirchhoff equation, Navier-Stokes equations and continuity equation supplemented by appropriate boundary and initial conditions. To solve this system of equations the finite difference method with a staggered grid is used. The results of computations obtained using authorial computer program are compared with ANSYS Fluent simulation. Computations are carried out for obstacles of various sizes and positions, and on this basis the conclusions are formulated.
    Źródło:
    Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 2; 121-132
    2299-9965
    Pojawia się w:
    Journal of Applied Mathematics and Computational Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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