1. Hydrodynamics of drop coalescence

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Initial as well as later dynamics of drop coalescence can have numerous applications in science and in industry. Both dynamics can dictate later-on evolution of the coalescence process and can generate numerous possibilities. Recently we showed (published in Physics of Fluids) that, during unbounded coalescence, flow in the bulk drops is inertial, the dominant resistance occurs through a viscous effect in the merging interface region and at the lesser extent in the bridge region. Early dynamics of drop coalescence is dominated by the Ohnesorge number (Oh), and later dynamics are dependent on how drops are bounded.

 

 

 

2. Stokesian dynamics simulation of colloidal interactions near a solid surface

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Almost all practical situation of colloidal suspension happens near a solid surface or in a confinement where wall plays a crucial role in it's dynamics. Wall effects for colloidal particles are long-ranged and transcend to many particles. Because of the linearity principles of the stokes flow, flow filed caused by many particles can be summed using superposition principles. I developed simulation code for relatively dilute suspension (0.56% v/v), and I am interested on dense suspension as well where better computational tricks and simplified scaling approximation of short range interactions can be employed (please see the video on this research from Video tab)

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3. Towards confinement-stabilized colloidal suspensions (simulating microgravity for colloids experiments)

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Within a colloidal suspension gravity may compromise the observation of governing physical interactions, especially those that are weak and/or take significant time to develop. Conducting the experiment in a long-term microgravity environment, as on the International Space Station, is a viable option to negate gravitational effects, though significant resources are required to do so. Therefore, we developed a horizontally rotating microfluidic system to investigate colloid suspension terrestrially in order to simulate microgravity conditions. Our goal is to establish long-term colloid suspension on lab based system. From simulation we are currently looking at best parameter-choice-scenarios to improve the system for long term suspension. For details see the poster for which we received best poster award in 2019 ASGSR annual meeting.

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4. Electric-field driven structure formation in a colloid suspension near a solid surface

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Electric field driven colloidal self assembly is widely known and practiced. Unlike settled experiments, our rotating platform can facilitate suspension near a solid surface. Therefore, in combination with rotating gravity colloids can form unique dynamic structures upon the application of electric field.

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