Proposal Numbers: 0626123 and 0626070 Principal Investigators: Singh, Pushpendra and Aubry, Nadine Affiliations: Foundation @NJIT and Carnegie-Mellon University Proposal Title: Collaborative Research: Efficient transport of bubbles and drops
Intellectual Merit:
An approach combining simulation, analysis and experiments is proposed to understand the mechanism that leads to a several-fold increase in the velocity of bubbles rising in viscoelastic liquids that occurs at a critical value of the bubble volume. The transient development of the bubble velocity and viscoelastic stresses, and their dependence on the cusp-like shape of the bubble's trailing end, will be investigated. The possibility of using this phenomenon in microfluidic devices to efficiently transport droplets in viscoelastic media, e.g., for high-throughput screening bioassays, will also be explored. The flow-induced stresses in viscoelastic liquids can cause instabilities that may drastically modify the usual Newtonian" solution and lead to a new solution. In the case of a rising bubble, for some parameter values, there is a critical bubble volume above which the flow is modified so that the drag coefficient is reduced by an order of magnitude compared to its value for slightly smaller bubbles.
Broader Impacts:
This research will be fully integrated with education, with the involvement of graduate and undergraduate students, particularly women and underrepresented minorities. The students involved will learn new, state-of-the-art CFD, analytical and experimental techniques for analyzing complex multiphase flows. Research results, in turn, will be incorporated in the fluid mechanics courses the PIs teach to illustrate (i) the difference in behavior of Newtonian and non- Newtonian fluids and (ii) how such differences can be exploited in applications. The proposed research will enhance the state-of-the-art understanding of complex multiphase flows of fundamental and industrial importance, with the potential to (i) have an impact on many industrial processes which encounter foams, emulsions, and manipulation of blood cells, DNA, proteins, as well as (ii) lead to novel techniques for efficient microfluidic transport. It will benefit society by expanding the toolbox to study multiscale and multiphysics phenomena, by resulting in innovative technologies, by encouraging the participation of women and under-represented minorities in science and technology, and by educating the public about exciting scientific research and technology innovations.
