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Title:	Numerical And Analytical Solutions Of Linear And Nonlinear Double-Diffusive Convection In A Fluid-Saturated Porous Layer
Authors:	Anas Abdallah Ahmad Altawallbeh (P57772)
Supervisor:	Ishak Hashim, Prof. Dr.
Keywords:	Numerical And Analytical Solutions Of Linear Numerical Solutions Of Linear Analytical Solutions Of Linear Nonlinear Double-Diffusive Convection Fluid-Saturated Porous Layer Turbulence
Issue Date:	12-Jan-2013
Description:	Controlling convective heat and mass transfer is one of the most important issues in recent years because of their effects on energy conservation and manufacturing processes. As a result, different problems in double-diffusive natural convection in a porous layer are solved and discussed in this thesis. Magnetohydrodynamics, differentially and partially heated and salted enclosures, thermal and solutal instabilities, internal heat and thermal non-equilibrium model are the main topics studied in this thesis. Numerical simulations are used to study double-diffusive convection inside porous enclosures. While, analytical method is used to study the thermohaline instability in a porous layer confined between two horizontal planes. Two-dimensional Newtonian and incompressible Darcy fluid is considered in the mathematical formulations. In addition, the Boussinesq approximation is adopted for the relationship between the density and the temperature and concentration. The fluid flow characteristics and convective heat and mass transfer inside a differentially heated and differentially salted porous enclosure are studied numerically. Two problems are solved and discussed. Numerical simulations are conducted under the effect of partially-heated and partially-salted boundaries and under the influence of a magnetic field. Finite volume method based on the power law scheme is used to discretize the system of the governing nonlinear partial differential equations, and the tridiagonal matrix algorithm is applied to solve the obtained system of algebraic equations. All the numerical algorithms are coded in MATLAB, and the validations of the codes are achieved with comparisons between our results and some previous published works. The results are presented in terms of average Nusselt number and average Sherwood number. In addition, the streamlines, isotherms and iso-concentration lines are also presented. The results show a significant effect of the heat and concentration segment's length and position on the heat and mass transfer processes. For the effect of magnetic field, it has been found that the increase of magnetic force has an effect to retard the strength of the flow inside the cavity and reduce the heat and mass transfer processes. In the instability part, two problems are solved and discussed. Linear and nonlinear double-diffusive convection in a fluid saturated anisotropic porous layer confined between two horizontal planes heated and salted from below with internal heat source and Soret effect are studied analytically. In addition, thermal non-equilibrium double-diffusive convection in a fluid-saturated porous layer confined between two horizontal planes heated and salted from below with Soret effect is also studied analytically. The analytical study is conducted based on both linear and nonlinear stability analysis. The normal mode technique is used in the linear stability analysis, while a minimal representation of truncated double Fourier series is used in the weak nonlinear analysis. The results are presented in terms of marginal stability curves for stationary and oscillatory modes. Heat and mass transfer have been obtained in terms of Nusselt number and Sherwood number, respectively. It is observed that internal Rayleigh number destabilizes the system for stationary and oscillatory modes. The negative (or positive) Soret parameter has a stabilizing (or destabilizing) effect on the stationary curves.,PhD
Pages:	182
Call Number:	QC880.4.T8 .A456 2013
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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