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Wyszukujesz frazę "boundary layer equations" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Similarity solutions to boundary layer equations for third-grade non-Newtonian fluid in special coordinate system
Rozwiązania podobieństwa równań warstwy przyściennej cieczy nieniutonowskiej trzeciego rzędu w specjalnym układzie współrzędnych
Autorzy:
Yurusoy, M.
Powiązania:
https://bibliotekanauki.pl/articles/281023.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
boundary layer equations
Lie's groups
third grade fluids
Opis:
Two dimensional equations of steady motion for third order fluids are expressed in a special coordinate system generated by the potential flow corresponding to an inviscid fluid. For the inviscid flow around an arbitrary object, the streamlines are the ...-coordinates and the velocity potential lines are ...-coordinates which form an orthogonal curvilinear set of coordinates. The outcome, boundary layer equations, is then shown to be indepedent of the bidy shape immersed into the flow. As the first approximation, it is assumed that the second grade terms are negligible compared to the viscous and third grade terms. The second grade terms spoil scanling transformation which is the only transformation leading to similarity solutions for a third grade fluid. By using Lie's group methods, infinitesimal generators of boundary layer equations are calculated. The equations are transformed into an ordinary differential system. Numerical solutions to the outcoming nonlinear differential equations are found by using a combination of the Runge-Kutta algorithm and a shooting technique.
W pracy przedstawiono dwuwymiarowe równania ruchu dla stacjonarnego przepływu cieczy trzeciego rzędu w specjalnym układzie współrzędnych. Równania wyprowadzono na bazie przepływu potencjalnego cieczy nielekkiej. Przy nielepkim opływie dowolnego obiektu linie prądu tworzą współrzędną ..., a linie potencjału prędkości współrzędną ... . Obydwie generują ortogonalny układ współrzędnych krzywoliniowych. Przy takim opisie postać równań warstwy przyściennej nie zależy od kształtu zanurzonego ciała poddanego opływowi. W pierwszym przybliżeniu założono, że wyrażenia drugiego rzędu są pomijalne w stosunku do członów wiskotycznych i trzeciego rzędu. Człony drugiego rzędu uniemożliwiają transformację skalowania, będącąjedynym przekształceniem prowadzącym do rozwiązań podobieństwa cieczy trzeciego rzędu. W pracy zastosowano metodę opartą na grupie Lie'a w generowaniu równań warstwy przyściennej przy pomocy wyrażeń infitezymalnych. Równania przekształcono do układu równań różniczkowych zwyczajnych. Numeryczne rozwiązanie równań nieliniowych uzyskano w drodze kombinacji algorytmu Runge-Kutta i techniki trymowania.
Źródło:
Journal of Theoretical and Applied Mechanics; 2003, 41, 4; 775-787
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
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:
Novel analytic-numerical model of free convection: with leading edge considered
Autorzy:
Leble, S.
Lewandowski, W. M.
Powiązania:
https://bibliotekanauki.pl/articles/1954434.pdf
Data publikacji:
2022-02-01
Wydawca:
Politechnika Gdańska
Tematy:
Navier-Stokes equations
Fourier-Kirchhoff equations
free convection
heat transfer
isothermal surface
boundary layer
vertical plate
leading edge
Równania Naviera-Stokesa
równanie Fouriera-Kirchhoffa
przenikanie ciepła
izoterma powierzchni
warstwa graniczna
płyty pionowe
Opis:
A novel solution of the free convection boundary problem is represent ed in analytical form for velocity and temperature for an isothermal vertical plate, as an example. These fields are built as a Taylor Series in the x coordinate with coefficients as functions of the vertical coordinate (y). We restrict ourselves by cubic approximation for both functions. The basic Navier-Stokes and Fourier-Kirchhoff equations and boundary conditions give links between coefficients and connected with free convection heat transfer phenomen on which define the analytical form of the solution as a function of the Grashof number only. In t he solution the non zero velocity of a fluid flow through a leading edge of the plate is take n into account. The solution in the form of velocity and temperature profiles is numerically evaluated and illustrated for air.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2014, 18, 2; 167--185
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of velocity profile in time dependent boundary layer flow of a modified power-law fluid of fourth grade
Autorzy:
Yurusoy, M.
Powiązania:
https://bibliotekanauki.pl/articles/265408.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
warstwa graniczna
płyny
płyn energetyczny
boundary layer equations
power-law fluids
fourth grade fluids
Opis:
This paper deals with the investigation of time dependent boundary layer flow of a modified power-law fluid of fourth grade on a stretched surface with an injection or suction boundary condition. The fluid model is a mixture of fourth grade and power-law fluids in which the fluid may display shear thickening, shear thinning or normal stress textures. By using the scaling and translation transformations which is a type of Lie Group transformation, time dependent boundary layer equations are reduced into two alternative ordinary differential equations systems (ODEs) with boundary conditions. During this reduction, special Lie Group transformations are used for translation, scaling and combined transformation. Numerical solutions have been carried out for the ordinary differential equations for various fluids and boundary condition parameters. As a result of numerical analysis, it is observed that the boundary layer thickness decreases as the power-law index value increases. It was also observed that for the fourth-grade fluid parameter, as the parameter increases, the boundary layer thickness decreases while the velocity in the y direction increases.
Źródło:
International Journal of Applied Mechanics and Engineering; 2020, 25, 2; 176-191
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Stability and Convergence of Difference Schemes for the Three-dimensional Equations of the Atmospheric Boundary Layer
Autorzy:
Temirbekov, A. N.
Urmashev, B. A.
Gromaszek, K.
Powiązania:
https://bibliotekanauki.pl/articles/226826.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
atmospheric boundary layer equations
difference scheme
approximation error
stability
convergence algorithms
numerical solution
Opis:
In this article we construct a finite-difference scheme for the three-dimensional equations of the atmospheric boundary layer. The solvability of the mathematical model is proved and quality properties of the solutions are studied. A priori estimates are derived for the solution of the differential equations. The mathematical questions of the difference schemes for the equations of the atmospheric boundary layer are studied. Nonlinear terms are approximated such that the integral term of the identity vanishes when it is scalar multiplied. This property of the difference scheme is formulated as a lemma. Main a priori estimates for the solution of the difference problem are derived. Approximation properties are investigated and the theorem of convergence of the difference solution to the solution of the differential problem is proved.
Źródło:
International Journal of Electronics and Telecommunications; 2018, 64, 3; 391-396
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Difference scheme for differential-difference problems with small shifts arising in computational model of neuronal variability
Autorzy:
Kodipaka, Mamatha
Emineni, Siva Prasad
Kolloju, Phaneendra
Powiązania:
https://bibliotekanauki.pl/articles/2174179.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
siatka niejednorodna
równanie różniczkowe
warstwa brzegowa
non-uniform grid
differential-difference equations
boundary layer
Opis:
The solution of differential-difference equations with small shifts having layer behaviour is the subject of this study. A difference scheme is proposed to solve this equation using a non-uniform grid. With the non-uniform grid, finite - difference estimates are derived for the first and second-order derivatives. Using these approximations, the given equation is discretized. The discretized equation is solved using the tridiagonal system algorithm. Convergence of the scheme is examined. Various numerical simulations are presented to demonstrate the validity of the scheme. In contrast to other techniques, maximum errors in the solution are organized to support the method. The layer behaviour in the solutions of the examples is depicted in graphs.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 1; 91--106
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytic-numerical model of a convective boundary layer and heat transfer on a horizontal cone
Autorzy:
Leble, S.
Pelc, W.
Powiązania:
https://bibliotekanauki.pl/articles/1943220.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska
Tematy:
natural convection
Fourier-Kirchhoff equations
boundary layer equation
isothermal cone
matching of Frobenius expansions
Opis:
An approximate analytical solution of a two dimensional problem for stationary Navier-Stokes, continuity and Fourier-Kirchhoff equations describing a free convective heat transfer from an isothermal cone is presented. The problem formulation is based on assumptions typical for natural convection: non-compressibility and the Boussinesq approximation. The solution is based on Frobenius expansions at the vicinities of two points: the initial point and the singular point of the boundary layer equation. Numerical matching of the expansions and Nusselt number evaluations are traced.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2009, 13, 1-2; 133-144
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for determination of flow at the plane, horizontal interface separating streams of two different fluids
Autorzy:
Prosnak, W. J.
Cześnik, P. P.
Powiązania:
https://bibliotekanauki.pl/articles/241051.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
interface
almost parallel streams of two fluids
boundary layer
ordinary differential equations
matching conditions
Opis:
The paper deals with the theoretical investigation of the phenomenon, which consists in generation - by wind - of the movement of water, the bodies of air and of water being separated by a horizontal, plane interface, which is identical with the free surface of water. A set of assumptions defining a physical model of the phenomenon, borrowed from Lock (1951), is introduced, as well as the mathematical description of this model. It reduces to a composite ordinary differential problem, containing two non-linear equations of the third order, which have to satisfy some boundary conditions. A novel method of solution of the differential problem just mentioned is presented in the paper. In the method use is made of exact formulae for coefficients of series representing the solution. The method seems to be competitive with the one given in the paper by Lock (1951).
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 2; 89-110
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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