*4.4. Skin Friction Coefficient*

The effects of variation of *Ha* and *α* on skin friction (*Cf*Re1/2 *<sup>x</sup>* and *Cf*Re1/2 *<sup>y</sup>* ) is shown in Figure 13. Figure 13 shows the plots for the skin friction by varying of Hartmann number and ratio parameter.

One may witness that:

