Hindawi Publishing Corporation Mathematical Problems in Engineering Volume 2010, Article ID 659023, 12 pages doi:10.1155/2010/659023 Research Article Mixed Convection Boundary Layer Flow over a Permeable Vertical Flat Plate Embedded in an Anisotropic Porous Medium Norfifah Bachok, 1 Anuar Ishak, 2 and Ioan Pop 3 1 Department of Mathematics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia 2 School of Mathematical Sciences, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia 3 Faculty of Mathematics, University of Cluj, CP 253, 3400 Cluj, Romania Correspondence should be addressed to Norfifah Bachok, norfifah@fsas.upm.edu.my Received 12 November 2009; Revised 19 April 2010; Accepted 17 May 2010 Academic Editor: Mehrdad Massoudi Copyright q 2010 Norfifah Bachok et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. An analysis is performed to study the heat transfer characteristics of steady mixed convection flow over a permeable vertical flat plate embedded in an anisotropic fluid-saturated porous medium. The effects of uniform suction and injection on the flow field and heat transfer characteristics are numerically studied by employing an implicit finite difference Keller-box method. It is found that dual solutions exist for both assisting and opposing flows. The results indicate that suction delays the boundary layer separation, while injection accelerates it. 1. Introduction Transport processes through porous media play important roles in diverse applications, such as in geothermal operations, petroleum industries, and many others. Excellent reviews on this topic can be found in the books by Ingham and Pop 1, Vafai 2, Nield and Bejan 3, Vadasz 4, and in the review paper by Magyari et al. 5. The study of convective heat transfer and fluid flow in porous media has received great attention in recent years. Most of the earlier studies Minkowycz and Cheng 6, Cheng and Minkowycz 7, and Badr and Pop 8 were based on Darcy’s law which states that the volume-averaged velocity is proportion to the pressure gradient. Kaviany 9 used the line integral method to study the heat transfer from a semi-infinite flat plate embedded in a fluid-saturated porous medium. Jang and Shiang 10 studied the mixed convection along a vertical adiabatic surface embedded in a porous medium. Few studies of convective boundary-layer flows in porous media using