Comment on “Effects of chemical reaction on free convective flow of a polar fluid through a porous medium in the presence of internal heat generation” by Patil and Kulkarni, Int. J. Thermal Sci. 47 (2008) 1043–1054

In this Letter we show that the paper by Patil and Kulkarni [P.M. Patil, P.S. Kulkarni, Effects of chemical reaction on free convective flow of a polar fluid through a porous medium in the presence of internal heat generation, Int. J. Thermal Sci. 47 (2008) 1043-1054] contains two errors which render their conclusions invalid. The first of these is a simple sign error. But the second involves the omission of part of the viscous dissipation term. We also show that the inclusion of this term yields an equation for the temperature field which cannot satisfy both the imposed boundary conditions.