Perform hand calculations to predict the expected maximum velocity using water and glycerol as materials at the end of the pipe. Compare your hand calculation results for the maximum velocity in the fully developed region with the corresponding values from COMSOL using water and glycerol.

Hint $1$: $u(r)=-\frac{R^2}{4}(\frac{dP}{dx})[1-(\frac{r}{R}{)}^2],u_{in}=u_{\text{a}\text{v}\text{g}}=\frac{V_{\text{m}\text{a}\text{x}}}{2}$