The performance of the employed kernel-depend methods was compared with those of the traditional models based on dimensional analysis. To achieve this aim, the formulas of Shahrokhnia & Javan (2003, 2005, 2006), and Zahedani et al. (2012) were used as depicted in Table 10. The results illustrated in Figure 13 and Table 11 reflect that the employed kernel-depend methods give superior performance than the selected dimensionless formulas.