In this video, we introduce Similitude. Often in fluid mechanics, we need to scale problems up or down to be able to better understand them or make easier observations. Similitude ensures that we preserve geometric, kinematic (velocity), and dynamic (force) scaling.

Through the video, we follow the work of William Froude on ship drag analysis and help him properly scale his problem down to something he can do in the lab. We learn all about how physics can break when we scale improperly, and how challenging scaling can be.

In practice, we need scaling for modeling and measurements of complex hydrodynamic and aerodynamic problems.

Free downloadable notes (PDF with white background) can be found at my website: https://sites.udel.edu/vanburen/educa...