The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
M Lucke - One of the best experts on this subject based on the ideXlab platform.
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influence of the Dufour Effect on convection in binary gas mixtures
Physical Review E, 1995Co-Authors: St Hollinger, M LuckeAbstract:Linear and nonlinear properties of convection in binary fluid layers heated from below are investigated, in particular for gas parameters. A Galerkin approximation for realistic boundary conditions that describes stationary and oscillatory convection in the form of straight parallel rolls is used to determine the influence of the Dufour Effect on the bifurcation behaviour of convective flow intensity, vertical heat current, and concentration mixing. The Dufour--induced changes in the bifurcation topology and the existence regimes of stationary and traveling wave convection are elucidated. To check the validity of the Galerkin results we compare with finite--difference numerical simulations of the full hydrodynamical field equations. Furthermore, we report on the scaling behaviour of linear properties of the stationary instability.
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onset of convection in binary gas mixtures role of the Dufour Effect
Physical Review A, 1992Co-Authors: W Hort, Stefan J Linz, M LuckeAbstract:The stability behavior of the conductive state of binary gas mixtures in the Rayleigh-B\'enard setup is significantly altered in comparison to binary liquid mixtures due to their different thermodynamic and transport properties. In particular, the Dufour Effect influences dramatically the topology and the existence ranges of the oscillatory and stationary instabilities for Dufour and Lewis numbers that are typical in gas mixtures. We present a detailed investigation of the changes of the stability properties for several types of boundary conditions including the realistic no-slip, impermeable ones.
A Mahdy - One of the best experts on this subject based on the ideXlab platform.
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Soret and Dufour Effect on double diffusion mixed convection from a vertical surface in a porous medium saturated with a non-Newtonian fluid
Journal of Non-newtonian Fluid Mechanics, 2010Co-Authors: A MahdyAbstract:Abstract A non-similar boundary layer analysis is presented to study the flow, heat and mass transfer characteristics of non-Darcian mixed convection of a non-Newtonian fluid from a vertical isothermal plate embedded in a homogeneous porous medium with the Effect of Soret and Dufour and in the presence of either surface injection or suction. The value of the mixed-convection parameter lies between 0 and 1. In addition, the power-law model is used for non-Newtonian fluids with exponent n 1 for dilatant fluids. Furthermore, the coordinates and dependent variables are transformed to yield computationally efficient numerical solutions that are valid over the entire range of mixed convection, from the pure forced-convection limit to the pure free-convection limit, and the whole domain of non-Newtonian fluids, from pseudoplastics to dilatant fluids. The numerical solution of the problem is derived using a Runge–Kutta integration scheme with Newton–Raphson shooting technique. Distributions for velocity, temperature and concentration, as well as for the rate of wall heat and mass transfer, have been obtained and discussed for various physical parametric values.
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mhd non darcian free convection from a vertical wavy surface embedded in porous media in the presence of soret and Dufour Effect
International Communications in Heat and Mass Transfer, 2009Co-Authors: A MahdyAbstract:Abstract The objective of this paper is to examine the combined Effect of spatially stationary surface waves and the presence of fluid inertia on the free convection along a heated vertical wavy surface embedded in an electrically conducting fluid saturated porous medium, subject to the diffusion-thermo (Dufour), thermo-diffusion (Soret) and magnetic field Effects. Diffusion-thermo implies that the heat transfer is induced by concentration gradient, and thermo-diffusion implies that the mass diffusion is induced by thermal gradient. The boundary-layer regime is considered where the Darcy–Rayleigh number is very large. A suitable coordinate transformation was considered to reduce the governing boundary-layer equations into non-similar form. The resulting nonlinear, coupled differential equations were solved numerically employing the Runge–Kutta algorithm with shooting iteration technique. Dimensionless velocity, temperature, concentration distributions, as well as local Nusselt number and Sherwood number are presented graphically for various values of Dufour number D u , Soret number S r , Buoyancy ratio N , amplitude of the wavy surface a , Lewis number Le , Grashof number Gr , and magnetic field Effect M g .
S R Mishra - One of the best experts on this subject based on the ideXlab platform.
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chemical reaction Effect on mhd viscoelastic fluid flow over a vertical stretching sheet with heat source sink
Ain Shams Engineering Journal, 2016Co-Authors: S Jena, G C Dash, S R MishraAbstract:Abstract The present paper intended to analyze the Effect of thermal diffusion (Soret) and diffusion-thermo (Dufour) Effect on MHD viscoelastic fluid flow over a porous vertical stretching sheet subject to variable magnetic field embedded in a porous medium in the presence of chemical reaction and heat source/sink. The method of solution involves similarity transformation. The coupled nonlinear partial differential equations governing flow, heat and mass transfer phenomena are reduced into set of nonlinear ordinary differential equations. The transformed equations are solved numerically by using Runge-Kutta fourth order method followed by shooting technique. The Effects of various parameters on the velocity, temperature and concentration fields are analyzed with the help of graphs. The numerical computation of skin friction, Nusselt number and Sherwood number is presented in a table. For validity of the numerical method applied here the work of previous authors is compared with the present one as a particular case by omitting the porosity, heat source/sink and chemical reaction parameters.
Stefan J Linz - One of the best experts on this subject based on the ideXlab platform.
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onset of convection in binary gas mixtures role of the Dufour Effect
Physical Review A, 1992Co-Authors: W Hort, Stefan J Linz, M LuckeAbstract:The stability behavior of the conductive state of binary gas mixtures in the Rayleigh-B\'enard setup is significantly altered in comparison to binary liquid mixtures due to their different thermodynamic and transport properties. In particular, the Dufour Effect influences dramatically the topology and the existence ranges of the oscillatory and stationary instabilities for Dufour and Lewis numbers that are typical in gas mixtures. We present a detailed investigation of the changes of the stability properties for several types of boundary conditions including the realistic no-slip, impermeable ones.
Peeyush Bhargava - One of the best experts on this subject based on the ideXlab platform.
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a numerical solution of unsteady mhd convection heat and mass transfer past a semi infinite vertical porous moving plate using element free galerkin method
Computational Materials Science, 2010Co-Authors: Rajesh Sharma, Rama Bhargava, Peeyush BhargavaAbstract:Abstract In this paper, the unsteady MHD free convection heat and mass transfer of viscous fluid flowing through a Darcian porous regime adjacent to a moving vertical semi-infinite plate under Soret and Dufour Effect have been examined. Viscous dissipation Effects are included in the energy equation. A uniform magnetic field is applied transversely to the direction of the flow. The differential equations governing the problem have been transformed by a similarity transformation into a system of non-dimensional differential equations which are solved numerically by element free Galerkin method. The influence of Grashof number (Gr), magnetic parameter (M), heat absorption parameter (Q), permeability parameter (K), Schmidt number (Sc), Soret number (Sr), and Dufour number (Du) on the velocity, temperature and concentration profiles are shown graphically. Some of the result has been compared with finite element method. Finally, the numerical values of local skin friction, local rate of heat transfer parameter and local mass transfer parameter are also presented in tabular form. The present problem finds significant applications in chemical engineering, materials processing, solar porous wafer absorber systems and metallurgy.
