We will see in Chapter 8 that the pressure drop in fully developed pipe flow is sometimes computed with the aid of a friction factor, defined by

\[ f=\frac{\Delta p}{\frac{1}{2} ho V^{2}} \frac{D}{\ell} \]

where \(V\) is the average velocity, \(D\) is the pipe diameter, and \(\ell\) is the length of pipe over which \(\Delta p\) occurs. For laminar fully developed flow, \(f\) can be evaluated from

\[ f=\frac{C}{\operatorname{Re}} \]

where \(C\) is a constant and \(\operatorname{Re}\) is the Reynolds number, given by \(\operatorname{Re}=ho V D / \mu\). Find the constant \(C\) for flow in a circular tube.