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    Wyświetlanie 1-13 z 13
    Tytuł:
    Axisymmetric free vibration of layered cylindrical shell filled with fluid
    Autorzy:
    Izyan, M. D. Nurul
    Sabri, Nur Ain Ayunni
    Hafizah, A. K. Nor
    Sankar, D. S.
    Viswanathan, K. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/2106463.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    drgania swobodne
    powłoka cylindryczna
    efekt Love'a
    axisymmetric
    free vibration
    cylindrical shell
    Love’s first approximation theory
    inviscid fluid
    spline approximation
    eigenvalues
    Opis:
    The aim of the study is to analyse the axisymmetric free vibration of layered cylindrical shells filled with a quiescent fluid. The fluid is assumed to be incompressible and inviscid. The equations of axisymmetric vibrations of layered cylindrical shell filled with fluid, on the longitudinal and transverse displacement components are obtained using Love’s first approximation theory. The solutions of displacement functions are assumed in a separable form to obtain a system of coupled differential equations in terms of displacement functions. The displacement functions are approximated by Bickley-type splines. A generalized eigenvalue problem is obtained and solved numerically for a frequency parameter and an associated eigenvector of spline coefficients. Two layered shells with three different types of materials under clamped-clamped boundary conditions are considered. Parametric studies are made on the variation of the frequency parameter with respect to length-to-radius ratio and length-to-thickness ratio.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2021, 26, 4; 63--76
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Unsteady Hartmann two-phase flow: the Riemann-sum approximation approach
    Autorzy:
    Jha, B. K.
    Babila, C. T.
    Isa, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/264967.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    przepływ dwufazowy
    przepływ niestacjonarny
    magnetohydrodynamika
    Riemann-sum approximation
    unsteady flow
    Hartmann two-phase flow
    Opis:
    We consider the time dependent Hartmann flow of a conducting fluid in a channel formed by two horizontal parallel plates of infinite extent, there being a layer of a non-conducting fluid between the conducting fluid and the upper channel wall. The flow formation of conducting and non-conducting fluids is coupled by equating the velocity and shear stress at the interface. The unsteady flow formation inside the channel is caused by a sudden change in the pressure gradient. The relevant partial differential equations capturing the present physical situation are transformed into ordinary differential equations using the Laplace transform technique. The ordinary differential equations are then solved analytically and the Riemann-sum approximation method is used to invert the Laplace domain into time domain. The solution obtained is validated by comparisons with the closed form solutions obtained for steady states which have been derived separately and also by the implicit finite difference method. The variation of velocity, mass flow rate and skin-friction on both plates for various physical parameters involved in the problem are reported and discussed with the help of line graphs. It was found that the effect of changes of the electric load parameter is to aid or oppose the flow as compared to the short-circuited case.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 891-904
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transient flow through a porous channel with ramped pressure gradient and velocity slip boundary condition
    Autorzy:
    Jha, Basant K.
    Yunus, Zainab Sa'id
    Powiązania:
    https://bibliotekanauki.pl/articles/2174168.pdf
    Data publikacji:
    2022
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    przepływ przejściowy
    prędkość
    ciśnienie
    transient flow
    velocity slip
    ramped pressure gradient
    Riemann-Sum approximation technique
    Opis:
    A transient flow formation of an incompressible fluid through a horizontal porous channel assuming a ramped pressure gradient is considered with the velocity slip boundary conditions. The flow is a laminar flow caused by ramped pressure gradient along the flow direction. The equation governing the flow is modeled, and solved by the Laplace transformation technique to obtain a semi-analytical solution under slip boundary conditions. It was noted that the flow velocity increases as the slip parameter is increased.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2022, 27, 1; 78--90
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Role of sudden application or withdrawal of magnetic field on MHD Couette flow
    Autorzy:
    Jha, B. K.
    Oni, M. O.
    Powiązania:
    https://bibliotekanauki.pl/articles/264957.pdf
    Data publikacji:
    2019
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    magnetohydrodynamika
    przepływ Couette'a
    liczba Hartmanna
    MHD
    Couette motion
    Riemann-sum approximation
    Hartmann number
    parallel plates
    Opis:
    This article investigates the impact of a sudden application or sudden withdrawal of a magnetic field on an unsteady MHD Couette flow formation in a parallel plate channel. The governing momentum equation is derived and solved exactly in Laplace domain using the Laplace transform technique with the necessary initial and boundary conditions to capture the present physical situation for the cases; sudden application or sudden withdrawal of a magnetic field. Due to the complexity of the solution obtained, the Riemann-sum approximation technique is used to transform the Laplace domain to time domain. During the course of graphical and tabular representations, results show that the Hartmann number, time and nature of application of a magnetic field play an important role in the transition from hydrodynamic to magnetohydrodynamic flow and vice-versa. Also, fluid velocity steady-state solution is independent on whether the magnetic field is fixed relative to the moving plate or to the fluid for sudden withdrawal of magnetic field. In addition, the application of a sudden magnetic field leads to a delay in the attainment of steady-state solution.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2019, 24, 4; 92-105
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Role of induced magnetic field on transient natural convection flow in a vertical channel: The Riemann sum approximation approach
    Autorzy:
    Jha, B. K.
    Sani, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/266260.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    induced magnetic field
    natural convection flow
    Riemann-sum approximation
    pole magnetyczne
    przepływ konwekcyjny
    twierdzenie Laplace'a
    Opis:
    This paper investigates the role of induced magnetic field on a transient natural convection flow of an electrically conducting, incompressible and viscous fluid in a vertical channel formed by two infinite vertical parallel plates. The transient flow formation inside the channel is due to sudden asymmetric heating of Chanel walls. The time dependent momentum, energy and magnetic induction equations are solved semi-analytically using the Laplace transform technique along with the Riemann-sum approximation method. The solutions obtained are validated by comparisons with the closed form solutions obtained for the steady states which hale been derived separately and also by the implicit finite difference method. Graphical results for the temperature, velocity, induced magnetic field, current density, and skin-friction based on the semi-analytical solutions are presented and discussed.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2015, 20, 1; 65-85
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Edge waves over a shelf
    Autorzy:
    Dolai, P.
    Dolai, D. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/264611.pdf
    Data publikacji:
    2019
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    fala brzegowa
    wielomian Gegenbauera
    relacja dyspersji
    shelf
    edge wave
    Havelock expansion
    Galerkin approximation
    Gegenbauer polynomial
    dispersion relation
    Opis:
    The problem considered in this paper is the derivation of properties of edge waves travelling along a submerged horizontal shelf. The problem is formulated within the framework of the linearized theory of water waves and Havelock expansions of water wave potentials are used in the mathematical analysis to obtain the dispersion relation for edge waves in terms of an integral. Appropriate multi-term Galerkin approximations involving ultra spherical Gegenbauer polynomials are utilized to obtain a very accurate numerical estimate for the integral and hence to derive the properties of edge waves over a shelf. The numerical results are illustrated in a table and curves are presented showing the variation of frequency of the edge waves with the width of the shelf.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2019, 24, 2; 453-460
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Oblique water wave diffraction by a step
    Autorzy:
    Dolai, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/264885.pdf
    Data publikacji:
    2017
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    finite step
    Havelock expansion
    Galerkin approximation
    Gegenbauer polynomial
    reflection and transmission coefficients
    aproksymacja Galerkina
    wielomian Gegenbauera
    odbicie
    Opis:
    This paper is concerned with the problem of diffraction of an obliquely incident surface water wave train on an obstacle in the form of a finite step. Havelock expansions of water wave potentials are used in the mathematical analysis to obtain the physical parameters reflection and transmission coefficients in terms of integrals. Appropriate multi-term Galerkin approximations involving ultraspherical Gegenbauer polynomials are utilized to obtain a very accurate numerical estimate for reflection and transmission coefficients which are depicted graphically. From these figures various interesting results are discussed.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2017, 22, 1; 35-47
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An overview of Millionschikovs quasi-normality hypothesis applied to turbulence
    Autorzy:
    Mamaloukas, C.
    Mazumdar, H. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/955186.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    turbulencja izotropowa
    fluktuacja prędkości
    magnetohydrodynamika
    Millionschikov's quasi-normality hypothesis
    isotropic turbulence
    zero-fourth cumulant approximation
    homogeneous turbulence
    Opis:
    In this paper, we examine the zero-fourth cumulant approximation that was applied to fluctuating velocity components of homogeneous and isotropic turbulence by M.D. Millionschikov. Since the publication of the remarkable paper of Millionschikov, many authors have applied this hypothesis to solve the closure problem of turbulence. We discuss here various studies by the other authors on the developments of this hypothesis and their applications to the incompressible velocity temperature, hydrodynamic and magnetohydrodynamic fluctuating pressure fields and the general magnetohydrodynamic turbulence field. Lastly, we discuss broadly the computational difficulties that arise in turbulence problems and their possible refinements. We include also some enlightments of the process of future work that could be undertaken in this field of research.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2014, 19, 1; 123-132
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Scattering of oblique water waves by an infinite step
    Autorzy:
    Dolai, P.
    Dolai, D. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/265749.pdf
    Data publikacji:
    2018
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    aproksymacja Galerkina
    wielomian Gegenbauera
    współczynnik transmisji
    infinite step
    Havelock expansion
    Galerkin approximation
    Gegenbauer polynomial
    reflection and transmission coefficients
    Opis:
    The present paper is concerned with the problem of scattering of obliquely incident surface water wave train passing over a step bottom between the regions of finite and infinite depth. Havelock expansions of water wave potentials are used in the mathematical analysis to obtain the physical parameters reflection and transmission coefficients in terms of integrals. Appropriate multi-term Galerkin approximations involving ultra spherical Gegenbauer polynomials are utilized to obtain very accurate numerical estimates for reflection and transmission coefficients. The numerical results are illustrated in tables.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2018, 23, 2; 327-338
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Scattering of internal waves by vertical barrier in a channel of stratified fluid
    Autorzy:
    Dolai, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/264794.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    stratified fluid
    internal wave
    vertical barrier
    stream function
    scattering matrix
    Boussinesq approximation
    eigen function expansion
    rozwarstwienie
    hydromechanika
    fala wewnętrzna
    Opis:
    The problem of two dimensional internal wave scattering by a vertical barrier in the form of a submerged plate, or a thin wall with a gap in an exponentially stratified fluid of uniform finite depth bounded by a rigid plane at the top, is considered in this paper. Assuming linear theory and the Boussinesq approximation, the problem is formulated in terms of the stream function. In the regions of the two sides of the vertical barrier, the scattered stream function is represented by appropriate eigen function expansions. By the use of appropriate conditions on the barrier and the gap, a dual series relation involving the unknown elements of the scattering matrix is produced. By defining a function with these unknown elements as its Fourier sine expansion series, it is found that this function satisfies a Carleman type integral equation on the barrier whose solution is immediate. The elements of the scattering matrix are then obtained analytically as well as numerically corresponding to any mode of the incident internal wave train for each barrier configuration. A comparison with earlier results available in the literature shows good agreement. To visualize the effect of the barrier on the fluid motion, the stream lines for an incident internal wave train at the lowest mode are plotted.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2015, 20, 3; 471-485
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Water wave scattering by an infinite step in the presence of an ice-cover
    Autorzy:
    Ray, S.
    De, S.
    Mandal, B. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/265982.pdf
    Data publikacji:
    2019
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    fala wodna
    pokrywa lodowa
    aproksymacja Galerkina
    water wave scattering
    ice cover
    infinite step
    integral equation
    Galerkin approximation
    reflection and transmission coefficients
    Opis:
    The classical problem of water wave scattering by an infinite step in deep water with a free surface is extended here with an ice-cover modelled as a thin uniform elastic plate. The step exists between regions of finie and infinite depths and waves are incident either from the infinite or from the finite depth water region. Each problem is reduced to an integral equation involving the horizontal component of velocity across the cut above the step. The integral equation is solved numerically using the Galerkin approximation in terms of simple polynomial multiplied by an appropriate weight function whose form is dictated by the behaviour of the fluid velocity near the edge of the step. The reflection and transmission coefficients are obtained approximately and their numerical estimates are seen to satisfy the energy identity. These are also depicted graphically against thenon-dimensional frequency parameter for various ice-cover parameters in a number of figures. In the absencje of ice-cover, the results for the free surface are recovered.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2019, 24, 4; 157-168
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of pin fin heat sink by application of CFD simulations and DOE methodology with neural network approximation
    Autorzy:
    Kasza, K.
    Malinowski, Ł.
    Królikowski, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/265135.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    wymiana ciepła
    optymalizacja projektu
    radiator
    sieci neuronowe
    modelowanie numeryczne
    polimery
    heat transfer
    design optimization
    heat sink
    neural network approximation
    numerical modeling
    thermally conductive polymer
    Opis:
    A design optimization of a staggered pin fin heat sink made of a thermally conductive polymer is presented. The influence of several design parameters like the pin fin height, the diameter, or the number of pins on thermal efficiency of the natural convection heat sink is studied. A limited number of representative heat sink designs were selected by application of the design of experiments (DOE) methodology and their thermal efficiency was evaluated by application of the antecedently validated and verified numerical model. The obtained results were utilized for the development of a response surface and a typical polynomial model was replaced with a neural network approximation. The particle swarm optimization (PSO) algorithm was applied for the neural network training providing very accurate characterization of the heat sink type under consideration. The quasi-complete search of defined solution domain was then performed and the different heat sink designs were compared by means of thermal performance metrics, i.e., array, space claim and mass based heat transfer coefficients. The computational fluid dynamics (CFD) calculations were repeated for the most effective heat sink designs.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2013, 18, 2; 365-381
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A review: differential transform method for semi-analytical solution of differential equations
    Autorzy:
    Rashidi, M. M.
    Rabiei, F.
    Naser Nia, S.
    Abbasbandy, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/265637.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    metoda transformacji różniczkowej
    równania różniczkowe
    metoda półanalityczna
    differential transform method
    differential transform - Pad'e approximation
    semi-analytical method
    differential equations
    fuzzy differential transformation method
    gS-differentiability
    Opis:
    In this article, the semi-analytical method known as the Differential Transform Method (DTM) for solving different types of differential equations is reviewed. First, basic definitions and formulas of DTM and Differential Transform-Padé approximation (DTM-Padé), which are used to increase the convergence and accuracy of DTM approximations, are discussed. Then both techniques of DTM and DTM-Padé, which have been successfully applied to partial differential equations, as well as the application of these methods in fluid mechanic and heat transfer are presented. In addition, the extension of DTM for integral differential equations and the fuzzy differential transformation method (FDTM) for fuzzy problems are discussed.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2020, 25, 2; 122-129
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

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