The problems are motivated by the production of oil, chemical processing, transport processes in living organisms and environmental flows. Fluid-fluid flows typically are hydrodynamically unstable leading to formation of waves, slugs and pulses, and possibly atomization. These disturbances in the flow strongly affect the pressure drop and heat and mass transfer rates. The basic strategy is to describe these very complex flows in terms of simpler model systems where fundamental discoveries can be achieved. Waves that form at the interface between two flowing immiscible liquids provide a perfect model system for studying flow disturbances in fluid-fluid flows.
Waves are initially uniform but can become very irregular with increasing flow rates.
Typical transition processes are formation of subharmonics by nonlinear interaction or focusing of some of the regular waves into solitary waves. Optical experimental techniques combined with image analysis provides information necessary to verify theoretical efforts that employ analytical and numerical solutions to the Navier-Stokes equations. Basic unanswered questions in gas-liquid flows in packed beds are the origin and mechanism of formation of pulses and their influence on reaction outcome. These issues are being addressed by a combined fluid mechanics-reaction, experimental and theoretical study done in conjunction with Professor Arvind Varma. These studies involve measurements of reaction rates in a sequential reaction that are intended to determine the effect of pulses on reaction outcome.