An Introduction to Dimensionless Parameters in the Study of Viscous Fluid Flows

It has been suggested that there is a need to deepen the understanding of fluid dynamics in the introductory physics course and to offer interesting experiments to do so.1 To address this need we have developed a laboratory experiment and the supporting analysis to demonstrate the role of viscosity and the interestingly mysterious use of dimensionless parameters in fluid dynamics.2 Since viscosity indicates the frictional dependence between the layers of a flowing fluid, a thoughtful student may ask why or when viscosity can be neglected. The laboratory experiment presented here uses common fluids to provide a concrete answer to this question and an easily understandable example of the role of dimensionless parameters in fluid dynamics.