## Research

My research spans classical fluid dynamics theory and experimental microfluidics involving multi-physics heat and mass transfer, with an emphasis on numerical simulations. The applications of my research range from the measurement and manipulation of particles and biomaterials for applications such as separations, detection, sorting, and filtration, to classical fluid dynamics theory for flow in bends and branching junctions. Some other projects that I have studied include modeling and predicting biophysical flow conditions, designing novel devices for measuring the electrokinetic potentials of particles and surfaces, and engineering new systems for efficient evaporative cooling and/or water purification.

## Contents

- Current research
- Previous research
- Dynamics of bubble bouncing at a liquid/liquid/gas interface
- Classical fluid dynamics in pipe flows
- High-speed axial-scanning wide-field microscopy for volumetric particle tracking velocimetry
- Point-source imbibition into dry aqueous foams
- Diffusive behaviors of circle-swimming nanomotors
- Evaporative cooling and water purification using thin-film flows over superhydrophilic surfaces

__Current research__

**Vortex dynamics in branching and bending flows**

**Papers:**

- *Oettinger, D.,
**Ault, J. T.**, Stone, H. A., and Haller, G. Invisible anchors trap particles in branching junctions.*Physical Review Letters*(2018), vol. 121, no. 5, pp. 054502. *Featured as Editor's Suggestion. **Ault, J. T.**, Fani, A., Chen, K. K., Shin. S., Gallaire, F., and Stone, H. A. Vortex-breakdown-induced particle capture in branching junctions.*Physical Review Letters*(2016), vol. 117, no. 8, pp. 1-5.- Shin., S.*,
**Ault, J. T.***, and Stone, H. A. Flow-driven rapid vesicle fusion via vortex trapping.*Langmuir*(2015), vol. 31, pp. 7178-7182. *The authors contributed equally to this work.

**Particle and biomaterial separations by diffusiophoresis**

**Papers:**

**Ault, J. T.**, Shin, S., and Stone, H. A. Diffusiophoresis in narrow channel flows.*Journal of Fluid Mechanics*(2018), vol. 854, pp. 420-448.- Shin, S.,
**Ault, J. T.**, Warren, P. B., and Stone, H. A. Accumulation of colloidal particles in flow junctions induced by fluid flow and diffusiophoresis.*Physical Review X*(2017), vol. 7, no. 4. **Ault, J. T.**, Ma, H., Bhowmik, D., and Shin, S. Diffusiophoretic mobility measurements of proteins by non-equilibrium molecular dynamics simulations.*In preparation.*

**Diffusiophoretic particle transport in confined systems**

**Papers:**

- Shin, S., Um, E., Sabass, B.,
**Ault, J. T.**, Rahimi, M., Warren, P. B., and Stone, H. A. Size-dependent control of colloid transport via solute gradients in dead-end channels.*Proceedings of the National Academy of Sciences*(2016), vol. 113, no. 2, pp. 257-261. - Shin, S.,
**Ault, J. T.**, Feng, J., Warren, P. B., and Stone, H. A. Low-cost zeta potentiometry using solute gradients.*Advanced Materials*(2017), vol. 29, no. 30. **Ault, J. T.**, Warren, P. B., Shin, S., and Stone, H. A. Diffusiophoresis in one-dimensional solute gradients.*Soft Matter*(2017), vol. 13, no. 47, pp. 9015-9023.

**Finite length effects of sliding rods near solid boundaries**

**Papers:**

**Ault, J. T.**, Rallabandi, B., and Stone, H. A. Finite length effects of sliding rods near solid boundaries.*In preparation.*

**Unsteady-steady transitions and tri-stability in swirling flows**

**Papers:**

- Chan, S. T.*,
**Ault, J. T.***, Haward, S. J., and Shen, A. Q. Unsteady-steady transition and tri-stability in a microfluidic swirling flow.*In preparation.**The authors contributed equally to this work.

__Previous research__

**Dynamics of bubble bouncing at a liquid/liquid/gas interface**

**Papers:**

- Feng, J., Muradoglu, M., Kim, H.,
**Ault, J. T.**, and Stone, H. A. Dynamics of a bubble bouncing at a liquid/liquid/gas interface.*Jounral of Fluid Mechanics*(2016), vol. 807, pp. 324-352.

**Classical fluid dynamics in pipe flows**

**Papers:**

**Ault, J. T.**, Chen, K. K., and Stone, H. A. Downstream decay of fully developed Dean flow.*Journal of Fluid Mechanics*(2015), vol. 777, pp. 219-244.**Ault, J. T.**, Rallabandi, B., Shardt, O., Chen, K. K., and Stone, H. A. Entry and exit flow in curved pipes.*Journal of Fluid Mechanics*(2017), vol. 815, pp. 570-591.

**High-speed axial-scanning wide-field microscopy for volumetric particle tracking velocimetry**

**Papers:**

- Chen, T.-H.,
**Ault, J. T.**, Stone, H. A., and Arnold, C. B. High-speed axial-scanning wide-field microscopy for volumetric particle tracking velocimetry.*Experiments in Fluids*(2017), vol. 58, no. 5, pp. 41.

**Point-source imbibition into dry aqueous foams****Papers:**

- Mensire, R.,
**Ault, J. T.**, Lorenceau, E., and Stone, H. A. Point-source imbibition into dry aqueous foams.*Europhysics Letters*(2016), vol. 113, no. 4, pp. 44002.

**Diffusive behaviors of circle-swimming nanomotors****Papers:**

- Marine, N. A., Wheat, P. M.,
**Ault, J. T.**, and Posner, J. D. Diffusive behaviors of circle-swimming motors.*Physical Review E (2013), vol. 87, no. 5, pp. 052305.*

**Evaporative cooling and water purification using thin-film flows over superhydrophilic surfaces**