A simple and affordable experiment to determine Reynolds number

Abstract

In this work, we present a simple and affordable experiment to determine the Reynolds number for water flowing through a cylindrical aperture. Commercially available equipment exists but often at high cost. Instead, the use of simple laboratory equipment (stopwatches, measuring cylinders and plastic bottles) allows an entire class to complete the experiment simultaneously. By measuring the mean bulk flow rates and calculating a value for the mean bulk speed of the fluid the Reynolds number (Re) can be determined. Using this experimental equipment we observed both laminar and turbulent flow, as confirmed through our calculated values of Re = 1100 ± 300 and Re = 9400 ± 700 respectively. Finally, we offer practical advice for carrying out these experiments as well as suggesting suitable further activities to make this activity accessible to various levels of study.