Correlating Sound and Flow Rate at a Tap

Laboratory tests were carried out to record the sound of water flowing through a tap and the corresponding flow rate. The results were analysed to determine a mathematical relationship between the sound signal and the flow rate. Three models, based on Fourier transforms of data in the frequency domain, were devised to estimate the flow rate of water as a function of the audible sound signal properties. The model was verified against independently recorded data from the experiments. An average error of 15% was determined when results were verified against 5 independently recorded data points. The hypothesis that actual flow rate could be estimated through the analysis of the recorded sound signal pattern was proven correct, but the accuracy of the results was relatively poor compared to mechanical meters. This study set the scene for further research into the use of microphones to assess outdoor water use.