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Conference Object Citation - WoS: 3Citation - Scopus: 6Drbem Solution of Natural Convective Heat Transfer With a Non-Darcy Model in a Porous Medium(Springer, 2015) Pekmen, B.; Tezer-Sezgin, M.This study presents the dual reciprocity boundary element (DRBEM) solution of Brinkman-Forchheimer-extended Darcy model in a porous medium containing an incompressible, viscous fluid. The governing dimensionless equations are solved in terms of stream function, vorticity and temperature. The problem geometry is a unit square cavity with either partially heated top and bottom walls or hot steps at the middle of these walls. DRBEM provides one to obtain the expected behavior of the flow in considerably small computational cost due to the discretization of only the boundary, and to compute the space derivatives in convective terms as well as unknown vorticity boundary conditions using coordinate matrix constructed by radial basis functions. The Backward-Euler time integration scheme is utilized for the time derivatives. The decrease in Darcy number suppresses heat transfer while heat transfer increases for larger values of porosity, and the natural convection is pronounced with the increase in Rayleigh number.Article Citation - WoS: 43Citation - Scopus: 48Mhd Flow and Heat Transfer in a Lid-Driven Porous Enclosure(Pergamon-elsevier Science Ltd, 2014) Pekmen, B.; Tezer-Sezgin, M.The mixed convection flow in a lid-driven square cavity filled with a porous medium under the effect of a magnetic field is studied numerically using the dual reciprocity boundary element method (DRBEM) with Houbolt time integration scheme. Induced magnetic field is also taken into consideration in terms of magnetic potential in solving magnetohydrodynamic (MHD) flow and temperature equations. Effects of the characteristic dimensionless parameters as Darcy (Da), Magnetic Reynolds (Rem), Grashof (Gr) and Hartmann (Ha) numbers, on the flow and heat transfer in the cavity are investigated at the final steady-state. It is found that the decrease in the permeability of porous medium and the increase in the intensity of the applied magnetic field cause the fluid to flow slowly. The convective heat transfer is reduced with an increase in Hartmann number. Magnetic potential circulates throughout the cavity with high magnetic permeability of the fluid. The combination of DRBEM with the Houbolt scheme has the advantage of using considerably small number of boundary elements and large time increments which results in small computational cost for solving the mixed convection MHD flow in a porous cavity. (C) 2013 Elsevier Ltd. All rights reserved.Article Citation - WoS: 16Citation - Scopus: 19Differential Quadrature Solution of Hyperbolic Telegraph Equation(Hindawi Publishing Corporation, 2012) Pekmen, B.; Tezer-Sezgin, M.Differential quadrature method (DQM) is proposed for the numerical solution of one- and two-space dimensional hyperbolic telegraph equation subject to appropriate initial and boundary conditions. Both polynomial-based differential quadrature (PDQ) and Fourier-based differential quadrature (FDQ) are used in space directions while PDQ is made use of in time direction. Numerical solution is obtained by using Gauss-Chebyshev-Lobatto grid points in space intervals and equally spaced and/or GCL grid points for the time interval. DQM in time direction gives the solution directly at a required time level or steady state without the need of iteration. DQM also has the advantage of giving quite good accuracy with considerably small number of discretization points both in space and time direction.
