Research

Sculpting of a dissolvable body by flowing water

Collaborate with Nick Moore, Megan Davies Wykes and Leif Ristroph

While fluid flows are known to promote dissolution of materials, such processes are poorly understood due to the coupled dynamics of the flow and receding surface. We study this moving boundary problem through experiments in which hard candy bodies dissolve in laminar, high-speed water flows. We find that different initial geometries are sculpted into a similar terminal form before ultimately vanishing, suggesting convergence to a stable shape-flow state. A model linking the flow and solute concentration shows how uniform boundary layer thickness leads to uniform dissolution, allowing us to obtain an analytical expression for the terminal geometry. Newly derived scaling laws predict that the dissolution rate increases with the square root of the flow speed and that the body volume vanishes quadratically in time, both of which are confirmed by experimental measurements.

Publications

Shape dynamics and scaling laws for a body dissolving in fluid flow ( PDF, link )
Jinzi M. Huang, M. Nicholas Moore, Leif Ristroph - J. Fluid Mech. Rapids (2015)

Talks and posters

Breaking Barriers - from Physics to Biology (II), 06/14/2014, Xi'an. ( Poster, link )
67th APS DFD conference, 11/25/2014, San Francisco. ( Slides, link )
Poster in room 105, Courant Institute. ( Poster )

Media Coverage

NPR - How Many Licks Does It Take To Get To A Tootsie Pop's Center? ( Link )
NY Post - NYU cracks the question: How many licks to the center of a Tootsie Pop? ( Link )
People - Sweet Science: Study Discovers How Many Licks It Takes to Reach the Center of a Tootsie Pop ( Link )
ABC News - Mathematicians Discover How Many Licks It Takes to Get to the Center of a Tootsie Pop ( Link )
Today - How many licks does it take to get to the center of a Tootsie Pop? ( Link )
NYU - Not candy crush - Scientists identify nature of candy sculpture ( Link )
人民网 - 菠萝科学奖数学奖得主:一颗棒棒糖引发奇妙科研之旅 ( Link)
新浪网 - “菠萝科学奖”数学奖:一根棒棒糖可以舔1000次 ( Link)
文汇报 - 科學研究:一根棒棒糖可以舔1000次 ( Link)
交大新闻网 - 交大毕业生黄金紫凭借“棒棒糖科学”获2015年菠萝科学奖数学奖 ( Link )