As the gap between the cylinders is reduced, κ increases and
λ becomes nearly constant for any value of s. This limiting case is
illustrated in Fig. 11, where λ is plotted as a function of κ for four
different values of n. It can be observed that, as κ increases, the
value of λ approaches the line λ = (κ + 1) /2. Once λ has been
determined, the velocity profile can be calculated and its integral
provides the volumetric flow rate Q [5].