Viscous force acting on the rod over the narrow annular region

Input(s)

L: Length $(\mathrm{ft})$

$\mu$ : Viscosity $(\mathrm{cP})$

$v_{o}$: Velocity $(\mathrm{ft} / \mathrm{s})$

$\kappa$: Ratio of Inner to Outer Ratio (fraction)

Output(s)

F: Force (N)

Formula(s)

$$ F=\frac{-2 * \pi * L * \mu * v_{o}}{\ln \left(\frac{1}{\kappa}\right)} $$

Reference(s)

Bird, R.B., Stewart, W.E. and Lightfoot, E.N. (2002). Transport Phenomena (Second Ed.). John Wiley \& Sons, Chapter: 2, Page: 65.