Temat: variation of parameters method - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Heat transfer study in a convective-radiative fin with temperature-dependent thermal conductivity and magnetic field using variation parameters method
Autorzy:: Sobamowo, G.
Jayesimi, L.
Femi-Oyetoro, J.
Powiązania:: https://bibliotekanauki.pl/articles/122666.pdf
Data publikacji:: 2017
Wydawca:: Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:: heat transfer study
convective-radiative fin
variation of parameters method
temperature-dependent thermal conductivity
magnetic field
wymiana ciepła
przewodność cieplna
żebro
Opis:: In this work, a heat transfer study is carried out in a convective-radiative straight fin with temperature-dependent thermal conductivity and a magnetic field using the variation of parameters method. The developed heat transfer model is used to analyze the thermal performance, establish the optimum thermal design parameters and investigate the effects of thermo-geometric parameters and non-linear thermal conductivity parameters on the thermal performance of the fin. The results obtained are compared with the results in literature and good agreements are found. The analysis can serve as basis for comparison of any other method of analysis of the problem and it also provides a platform for improvement in the design of fin in heat transfer equipment.
Źródło:: Journal of Applied Mathematics and Computational Mechanics; 2017, 16, 3; 85-96
2299-9965
Pojawia się w:: Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Some applications of Noether’s theorem
Autorzy:: Montiel-Pérez, J. Yaljá
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:: https://bibliotekanauki.pl/articles/1166045.pdf
Data publikacji:: 2018
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:: Complex Riemann-Silberstein vector
Duality rotations
Ignorable variable
Invariance of the action
Lanczos variational method
Linear differential equation of second order
Maxwell equations
Noether’s theorem
Variation of parameters
Variational symmetry
Opis:: If the action S= ∫_(t_1)^(t_2)▒〖L(q,〗 (q,) ̇t) dt is invariant under the infinitesimal transformation t ̃=t+ε τ(q,t), q ̃_r= q_r+ε ξ_r (q,t),r=1,… ,n, with ε=constant ≪1, then the Noether’s theorem permits to construct the corresponding conserved quantity. The Lanczos approach employs to ε= q_(n+1) as a new degree of freedom, thus the Euler-Lagrange equation for this new variable gives the Noether’s constant of motion. Torres del Castillo and Rubalcava-García showed that each variational symmetry implies the existence of an ignorable coordinate; here we apply the Lanczos approach to the Noether’s theorem to motivate the principal relations of these authors. The Maxwell equations without sources are invariant under duality rotations, then we show that this invariance implies, via the Noether’s theorem, the continuity equation for the electromagnetic energy. Besides, we demonstrate that if we know one solution of p(x)y''+q(x)y'+r(x)y=0, then this Lanczos technique allows obtain the other solution of this homogeneous linear differential equation.
Źródło:: World Scientific News; 2018, 106; 69-80
2392-2192
Pojawia się w:: World Scientific News
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Variation of parameters method for a three-dimensional problem of condensation film on an inclined rotating disk
Autorzy:: Güngör, Osman
Arslantürk, Cihat
Powiązania:: https://bibliotekanauki.pl/articles/122445.pdf
Data publikacji:: 2019
Wydawca:: Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:: condensation
rotating inclined disk
nonlinear ordinary differential equations
variation of parameters method
VPM
kondensacja
nieliniowe równania różniczkowe zwyczajne
metoda zmiany parametrów
Opis:: In this paper, the steady three-dimensional problem of condensation film on an inclined rotating disk is considered. The governing nonlinear partial differential equations are reduced to the nonlinear ordinary differential equations system by a similarity transform. The equation system is solved by the variation of parameters method (VPM) which is rather used to solve nonhomogeneous linear differential equations but can also be used to solve nonlinear differential equations. This method has not previously been used to solve a nonlinear condensation problem. The dimensionless velocity and temperature profiles are shown, and the influence of Prandtl number and rotation ratio on the flow field and the Nusselt number are discussed in detail. In order to assess the accuracy of the solutions obtained by this method, the problem is also solved numerically using the Matlab bvp4c solver. The validity of our solutions is verified by the numerical results.
Źródło:: Journal of Applied Mathematics and Computational Mechanics; 2019, 18, 1; 15-28
2299-9965
Pojawia się w:: Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Application of variation of the parameters method for micropolar flow in a porous channel
Autorzy:: Güngör, Osman
Arslantürk, Cihat
Powiązania:: https://bibliotekanauki.pl/articles/1839802.pdf
Data publikacji:: 2020
Wydawca:: Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:: micropolar flow
porous channel
variation of parameters method
przepływ mikropolarny
metoda zmiany parametrów
kanał porowaty
Opis:: This work devoted to study the injective micropolar flow in a porous channel. The flow is driven by suction or injection on the channel walls, and the micropolar model is used to characterize the working fluid. The governing nonlinear partial differential equations are reduced to the nonlinear ordinary coupled differential equations by using Berman’s similarity transformation. These equations are solved for large mass transfer via variation of parameters method (VPM) which has been used effectively in the solution of nonlinear equations recently. This method has not previously been applied to a problem of micropolar flow. The results of the variation of parameters method are found to be in excellent agreement with the results of the Matlab bvp4c solver (NUM). With this validity, the effects of the some important parameters on the velocity and rotation profile of micropolar flow are discussed in detail. It can be seen that increases in the values N1 and N3 have different results in comparison with N2 increasing.
Źródło:: Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 1; 17-29
2299-9965
Pojawia się w:: Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Application of variation of the parameters method for micropolar flow in a porous channel
Autorzy:: Güngör, Osman
Arslantürk, Cihat
Powiązania:: https://bibliotekanauki.pl/articles/122970.pdf
Data publikacji:: 2020
Wydawca:: Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:: micropolar flow
porous channel
variation of parameters method
przepływ mikropolarny
metoda zmiany parametrów
kanał porowaty
Opis:: This work devoted to study the injective micropolar flow in a porous channel. The flow is driven by suction or injection on the channel walls, and the micropolar model is used to characterize the working fluid. The governing nonlinear partial differential equations are reduced to the nonlinear ordinary coupled differential equations by using Berman’s similarity transformation. These equations are solved for large mass transfer via variation of parameters method (VPM) which has been used effectively in the solution of nonlinear equations recently. This method has not previously been applied to a problem of micropolar flow. The results of the variation of parameters method are found to be in excellent agreement with the results of the Matlab bvp4c solver (NUM). With this validity, the effects of the some important parameters on the velocity and rotation profile of micropolar flow are discussed in detail. It can be seen that increases in the values N₁ and N₃ have different results in comparison with N₂ increasing.
Źródło:: Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 1; 17-29
2299-9965
Pojawia się w:: Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Thermal analysis of longitudinal a porous fin with temperature-dependent internal heat generation using the variation of parameters method
Autorzy:: Güngör, Osman
Arslantürk, Cihat
Powiązania:: https://bibliotekanauki.pl/articles/1839762.pdf
Data publikacji:: 2020
Wydawca:: Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:: variation of parameters method
porous fin
heat generation
exact solution
metoda wariacji parametrów
żebro porowate
wytwarzanie ciepła
dokładne rozwiązanie
Opis:: The present study investigates the thermal performance of longitudinal a porous fin with temperature-dependent internal heat generation. The Darcy model is utilized to obtain the differential form of the governing equation that solves the nonlinear temperature distribution equation using the method of variation of parameters. Although this method is applied to solve both linear and nonlinear differential equations, there exist rare applications of this method to solve nonlinear heat transfer problems. In the present study, we applied the method to estimate the thermal analysis of the porous fin exposed to convection. The heat generation is assumed as a function of temperature. The effects of the convection parameter Nc, internal heat generation ɛ, porosity Sh, and generation number G parameter on the dimensionless temperature distribution are discussed in detail. The accuracy of the variation of parameters method is verified through comparison with homotopy perturbation method and the Matlab bvp4c solver (NUM). The results have disclosed that the variation of parameters method can be used as a very effective and practical approach for further studies of the porous medium.
Źródło:: Journal of Applied Mathematics and Computational Mechanics; 2020, 19, 3; 5-16
2299-9965
Pojawia się w:: Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:: Biblioteka Nauki

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