Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Mechanical and Aerospace Engineering

Committee Chair(s)

Tadd T. Truscott


Tadd T. Truscott


Jesse Belden


Som Dutta


Greg Droge


A droplet of fluid can slide or roll down an angled surface if the droplet doesn’t stick to the plate (e.g., droplets on glass). The most common surface to allow for such this motion are hydrophobic surfaces. One example is a freshly waxed car where the rain beads up and rolls off. Another example is if a pan is heated to a high enough temperature then when small amounts of water are added the droplet will skitter around on the surface for a moment before boiling away. This high temperature effect where droplets rest on a vapor layer underneath cause by the heat is called the Leidenfrost point. One might ask which surface type will encourage a droplet to go down the surface fastest? Herein an analysis and comparison of droplets on both of these types of surfaces is performed, with consideration given to the size of the droplet, the angle of the surface, and the type of droplet by varying the relative thickness or viscosity. The droplet velocity and acceleration are compared and the hydrophobic surfaces with water have the most consistent high velocities. However, making the droplets more viscous slows down the droplets on hydrophobic surface more effectively than on Leidenfrost ones. Finally, both surfaces can produce a form of thrust if conditions are right.