Abstract
Flows of non-Newtonian fluids passing a flat external surface with zero incidence angle was studied theoretically. The constitutive equation used in the present study is the Phan Thien-Tanner (PTT) type with the network theory, and the simple power law is used for comparison. The thickness of the boundary layer and the friction coefficient are calculated in order to examine the effects of the breakage index and the slip parameter in the shear behavior. The Von Karman integral equation is solved numerically with a similar solution of the velocity profile using the newly defined shape factor. The calculation results for shear thinning liquids indicate that the thickness of the boundary layer and the friction coefficient are dependent upon the slip parameter and the breakage index, where a choice of non-zero breakage index without the effect of the normal stress terms yields similar results to the power law case. It is revealed that the friction coefficient (wall shear stress) has a peak value at the entrance region of the plate, whereas such a symotom is not seen in the case of the power law and the Newtonian flows.
