Formula: Poiseuille's Equation

Volumetric Flow Rate

Unit
Volumetric Flow Rate (Volume velocity) is the volume of a fluid (e.g. water) that passes through a cross-sectional area of a pipe per second. The volume flow is due to a pressure difference $$\Delta \mathit{\Pi} = \mathit{\Pi}_1 - \mathit{\Pi}_2$$ between the ends of the pipe.

Length

Unit
Length of a pipe through which a fluid moves.

Dynamic viscosity

Unit
Viscosity $$\eta$$ (pronounced: Eta) is a property of a fluid (liquid or gas) and describes how difficult it is to move a body through this fluid.

Liquid Viscosity $$\eta$$
Olive oil$$108 \cdot 10^{-3} \, \frac{\mathrm{kg}}{ \mathrm{m}\cdot \mathrm{s} }$$
Honey$$10\,000 \cdot 10^{-3} \, \frac{\mathrm{kg}}{ \mathrm{m}\cdot \mathrm{s} }$$
Glycerin$$1500 \cdot 10^{-3} \, \frac{\mathrm{kg}}{ \mathrm{m}\cdot \mathrm{s} }$$
Water$$1.008 \cdot 10^{-3} \, \frac{\mathrm{kg}}{ \mathrm{m}\cdot \mathrm{s} }$$
Tar$$100\,000 \cdot 10^{-3} \, \frac{\mathrm{kg}}{ \mathrm{m}\cdot \mathrm{s} }$$
Viscosity of some liquids.

Pressure at one end of the pipe. $$\Pi$$ is pronounced as "Pi".