## Honors Theses - All

April 2018

Greg Voth

Physics

#### Language

English (United States)

#### Abstract

In a publication in 1871, Lord Kelvin, a notable $19^\text{th}$ century scientist, hypothesized the existence of an isotropic helicoid. He predicted that such a particle would be isotropic in drag and rotation translation coupling, and also have a handedness that causes it to rotate. Since this work was published, theorists have made predictions about the motion of isotropic helicoids in complex flows. Until now, no one has built such a particle or quantified its rotation translation coupling to confirm whether the particle has the properties that Lord Kelvin predicted. In this thesis, we show experimental, theoretical, and computational evidence that all conclude that Lord Kelvin's geometry of an isotropic helicoid does not couple rotation and translation. Even in both the high and low Reynolds number regimes, Lord Kelvin's model did not rotate through fluid. While it is possible there may be a chiral particle that is isotropic in drag and rotation translation coupling, this thesis presents compelling evidence that the geometry Lord Kelvin proposed is not one. Our evidence leads us to hypothesize that an isotropic helicoid does not exist.

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