Polymer Drag Reduction
- Addition of trace amounts of polymer can reduce friction by up to 80%
- We developed a polymer drag reduction system for the 2010 America’s Cup
- We currently study polymer mechanical degradation, modification of the near-wall velocity profiles, and polymer modified coherent structures.
Helicopter Rotor Hub Wakes
- Helicopter rotor hub wakes are responsible for up to 30% of the parasitic drag on a helicopter
- Due to the complex flow, the wake and its interaction with other components is poorly understood
- We characterize the wake, identify dominate coherent structures, and aim to control them to mitigate the losses.
Bat Ear Aerodynamics
- The Brazilian free-tailed bat has small bumps on the leading-edge of their ears that match the pattern observed on humpback whales
- Whale “tubercles” are known to increase their maneuverability
- EFPL has experimentally demonstrated that the tubercles reduce drag and are currently working to identify the mechanism responsible for this observation
Conformal Vortex Generators
- Vortex generators are a common passive flow control device used on airplane wings
- The farther they stick into the flow, the less efficient they are at reducing drag.
- We showed that CVGs can produce coherent structures on the order of the boundary layer thickness even though they are a fraction of that height.