Kee Onn Fong, PhD

Active & multiphase flows | How the oceans breathe


Applied Physics Laboratory, University of Washington, Seattle

I am a scientist interested in the flow of matter and the laws that govern them. 

I obtained my PhD at the University of Minnesota with Filippo Coletti, studying the transport of solid particles in air with a turbulent boundary layer, and also the clustering of solid particles at high concentrations in a circulating fluidized bed riser. At the University of Washington, I first studied liquid sprays with Alberto Aliseda in the Mechanical Engineering department, conducting experiments and theoretical analysis on droplet formation and distribution in high ambient pressure conditions. 

Currently, I am studying the exchange of gases between the ocean and atmosphere and how bubbles mediate this exchange. I work with Craig McNeil at the Applied Physics Laboratory - University of Washington, and am also part of the Environmental Fluid Mechanics group. 

I am currently in search of a tenure-track faculty position. I can be reached any time at keeonnfong [at] gmail.com. 

Research overview

How the oceans breathe

Air-sea gas exchange plays an important role in our ecosystem. Oxygenation supports life in the ocean, and carbon dioxide absorption reduces the effect of human fossil fuel emission. 

How do bubbles affect this exchange? How would that change as the Earth's climate becomes warmer? What are the effect of structures in the ocean on vertical transport of scalars? 

Shape-changing particles in fluid flows

The overarching challenge of the 21st century is defined by energy. I am interested in combining soft matter and fluid mechanics to offer solutions to the global energy challenge. 

By creating programmable, active particles to control fluid turbulence, we can create designer complex fluids where control of heat and mass transport properties is possible. 

Current/past projects

Bubble-mediated air-sea gas exchange in the Labrador Sea

I am currently studying air-sea gas exchange in the Labrador Sea, a site of deep water formation and an important part of the ocean engine. I focus on air-sea gas exchange in wintertime convection conditions - how convection affects the transport of bubbles and Langmuir currents and ultimately gas exchange. 

As part of this project, I participated in a 5-week field measurement campaign in Nov-Dec 2023 aboard the R/V Maria S Merian (Germany), deploying autonomous underwater vehicles (AUVs) to observe bubbles and currents using sonars and acoustic Doppler profilers, as well as measure in situ gas fluxes using dissolved gas sensors.  Funded by the National Science Foundation, with cooperation from collaborators in Germany, the UK, and Canada. 

High pressure gas-liquid atomization

A novel experiment where a coaxial liquid-gas atomizer operates in a high-pressure environment. We study the effect of elevated ambient pressures on the atomization dynamics of the liquid column & the resulting droplet formation and dispersion, and compare with predictions from Kelvin-Helmholtz and Rayleigh-Taylor instabilities.  Funded by the U.S. Navy under the MURI Spray Control Project. 

Clustering in dense particle-laden flows

Inspired by particle solar receivers and circulating fluidized beds, a setup of falling particles against rising air flow allows for controllable solids volume fractions to study particle clustering, uncovering a critical volume fraction beyond which clusters form and alters the bulk flow.  Funded by NSF, U.S. Army and the State of Minnesota. 

Preferential concentration of particles

A canonical turbulent channel flow is laden with solid particles, with sizes such that they exhibit turbophoresis and streak formation near the walls, and preferential concentration in the centerplane. Varying the solids volume fraction also revealed a transition from one-way to two-way coupling between the solids and the gas phase. 

Microfluidics 

Several microfluidic chips are used to significantly accelerate the time to identify and quantify microbes in a biological sample and test them for antibiotic resistance. Applications include rapid diagnosis of urinary tract infections. 

About me

Education

University of Minnesota Twin-Cities, Minneapolis, MN 

PhD, Aerospace Engineering and Mechanics, 2021

MSc, Aerospace Engineering and Mechanics, 2018

BEng, Aerospace Engineering and Mechanics, 2015

Research interests

Experimental fluid mechanics, multiphase flows, soft matter, active matter, rapid granular flows, heat and mass transport, collective dynamics, elasto-inertial turbulence, microfluidics

Science outreach

Leadership

Industrial experiences  

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