Problem 1.336

The cross-sectional radius of a pipeline decreases gradually as $r=r_{9} \mathrm{e}^{-\alpha x}$, where $\alpha=0.50 \mathrm{~m}^{-1}, x$ is the distance from the pipeline inlet. Find the ratio of Reynolds numbers for two cross-sections separated by $\Delta x=3.2 \mathrm{~m}$.