Splat! : Modelling the Relationship Between Drop Height and Maximum Spreading Diameter of Various Liquids

The physics behind the spreading of falling droplets is a subject of ongoing debate, with numerous models proposed to describe the behaviour. This project explores the relationship between drop height and maximum spreading diameter (Dmax) of water, ethanol, canola oil, and 1% milk. Videos of droplets falling onto a flat surface, taken on a 240 FPS camera, were analysed to determine Dmax and compared with two proposed models based on (1) energy conservation and (2) inertia and mass conservation. The fit of the models to the data was assessed using t-scores and f-tests. Using the determined values, a Python simulation was created to generate a predicted plot of the resultant disk from any inputted drop height and volume. Unexpectedly, neither original proposed model accurately described the data due to the lack of an intercept (since Dmax ≠ 0 when drop height is 0 m). Including an intercept improved the goodness-of-fit of both models; in these adjusted models, the model based on energy conservation was a better fit to the data. Incorporation of other properties, such as viscosity, may allow more accurate predictions through simulation. Applications include the transmission of waterborne disease, industrial processes, and forensic bloodstain analysis.Science, Faculty ofUnreviewedUndergraduat