2013-14

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Browsing 2013-14 by Subject "Gangadharaiah"

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    Bernard-Marangoni Convection in a Fluid Layer Overlying a Layer of an Anisotropic Porous Layer with Deformable Free Surface
    (2013-08-06T06:52:23Z) Gangadharaiah, Y. H.; Suma, S.P
    The linear stability of Bernard-Marangoni convection in a two-layer system consisting of a fluid layer overlying a porous layer with anisotropic permeability and thermal diffusivity is studied. The upper fluid surface, free to atmosphere is considered to be deformable. Flow in the porous medium is assumed to be governed by Darcy’s law; the Beavers-Joseph condition is applied at the interface between the two layers. The boundaries are considered to be rigid, however permeable, and insulated to temperature perturbations. The eigen value problem is solved using a regular perturbation technique with wave number a as perturbation parameter. It is found that the Crispation number, Bond number, depth of the relative layers, mechanical and thermal anisotropy parameters have a profound effect on the stability of the system. Decreasing the Crispation number and mechanical anisotropy parameter and increasing the Bond number and thermal anisotropy parameter leads to stabilization of the system. Also, the effect of the ratio of the fluid to porous layer thickness along with the other various physical parameters on the control of convection is analysed in detail.
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    Effect of Internal Heat Generation on the Onset of Darcy–Benard Convection in Porous Media
    (2013-07-12T12:20:30Z) Gangadharaiah, Y H; Suma, S.P
    The onset of Darcy–Benard penetrative convection in a liquid saturated porous layer of high permeability of practical importance is investigated by employing the Brinkman–Forchheimer–Lapwood extended Darcy flow model with fluid viscosity different from effective viscosity. The lower boundary is taken to be rigid and isothermal and the upper surface is free and subject to the general thermal condition. The critical eigen values are obtained numerically, in general, using Galerkin method. The stability of the system is found to be dependent on the dimensionless internal heat source strength Ns, permeability parameter and the ratio of effective viscosity to fluid viscosity. It is observed that the increase in the value of permeability parameter is to delay while increase in the value of internal heat source strength is to hasten the onset of convection in a fluid saturated porous layer.
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    Penetrative convection via internal heating in superposed fluid and anisotropic porous layers with throughflow
    (2014-04-04T07:49:39Z) Gangadharaiah, Y. H; Suma, S.P; Nagarathnamma, H
    The onset of thermal convection due to heating from below in a system consisting of a fluid layer overlying a porous layer with anisotropic permeability and thermal diffusivity is studied. The onset of penetrative convection simulated via internal heating in the presence of a vertical throughflow. Flow in the porous medium is governed by Forchheimer-extended Darcy equation and the Beavers–Joseph slip condition is applied at the interface between the fluid and the porous layers. The boundaries are considered to be rigid, however permeable, and insulated to temperature perturbations. The eigen value problem is solved using a regular perturbation technique with wave number as a perturbation parameter. It is found that the depth of the relative layers, the direction of throughflow, the presence of volumetric internal heat source in fluid and/or porous layer and mechanical and thermal anisotropy parameters have a profound effect on the stability of the system. Decreasing the mechanical anisotropy parameter and increasing the thermal anisotropy parameter leads to stabilization of the system. Besides, the possibility of control of thermal convection by suitable choice of physical parameters is discussed in detail.
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    Penetrative Marangoni Convection in Superposed Fluid and Porous Layers with Deformable Free Surface
    (2014-04-04T07:44:58Z) Gangadharaiah, Y. H
    The linear stability analysis of Marangoni convection in a composite system comprised of an incompressible fluid-saturated porous layer underlying a layer of same fluid is considered. The upper fluid surface, free to atmosphere is considered to be deformable and subjected to temperature-dependent surface tension. The fluid flow in the porous layer is governed by the Forchheimer-extended Darcy equation and Beavers-Joseph condition is employed at the interface between the two layers. The resulting eigen value problem is solved exactly. The ratio of fluid layer thickness to porous layer thickness, ζ, the Crispation number, Bond number and the presence of volumetric internal heat source in fluid and/or porous layer play a decisive role on the stability characteristics of the system. In addition, the effects of boundary conditions and along with the other various physical parameters on the control of convection is analyzed in detail.