Note that the two dimensionless quantities are not unique and depend on which of the n = 5 variables are chosen as the k = 3 dimensionally independent basis variables, which, in this example, appear in both dimensionless quantities. The Reynolds number and power number fall from the above analysis if ρ ρ , n, and D are chosen to be the basis variables. If, instead, μ μ , n, and D are selected, the Reynolds number is recovered while the second dimensionless quantity becomes N R e p = P μ μ D 3 n 2 . We note that N R e p is the product of the Reynolds number and the power number.