Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Variable Viscosity on Magnetohydrodynamic Fluid Flow and Heat Transfer over an Unsteady Stretching Surface with Hall Effect | Hindawi Publishing Corporation Boundary Value Problems Volume 2o10 Article ID 257568 20 pages doi 2010 257568 Research Article Variable Viscosity on Magnetohydrodynamic Fluid Flow and Heat Transfer over an Unsteady Stretching Surface with Hall Effect S. Shateyi1 and S. S. Motsa2 1 School of Mathematical and Natural Sciences University ofVenda Private Bag X5050 Thohoyandou 0950 South Africa 2 Department of Mathematics University of Swaziland Private Bag 4 Kwaluseni M201 Swaziland Correspondence should be addressed to S. Shateyi Received 16 July 2010 Accepted 16 August 2010 Academic Editor Vicentiu D. Radulescu Copyright 2010 S. Shateyi and S. S. Motsa. 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. The problem of magnetohydrodynamic flow and heat transfer of a viscous incompressible and electrically conducting fluid past a semi-infinite unsteady stretching sheet is analyzed numerically. The problem was studied under the effects of Hall currents variable viscosity and variable thermal diffusivity. Using a similarity transformation the governing fundamental equations are approximated by a system of nonlinear ordinary differential equations. The resultant system of ordinary differential equations is then solved numerically by the successive linearization method together with the Chebyshev pseudospectral method. Details of the velocity and temperature fields as well as the local skin friction and the local Nusselt number for various values of the parameters of the problem are presented. It is noted that the axial velocity decreases with increasing the values of the unsteadiness parameter variable viscosity parameter or the Hartmann number while the transverse velocity increases as the Hartmann number increases. Due to increases in thermal diffusivity parameter temperature