Farrell teaches courses in thermodynamics and fluid mechanics and is a member of the American Society of Mechanical Engineers, the OpticalSociety of America and the Society of Automotive Engineers. His recent work includes studies of high-pressure fuel sprays and spray-wall interactions, studies of three-dimensional gas flows using image velocimetry and particle sizing, and studies of heat and mass transfer in combusting systems. Recent optical diagnostic developments include enhancement particle sizing systems, high-speed full-field velocity measurement systems, and planar laser-induced fluorescence techniques. Professor Farrell's major research areas include fluid mechanics, combustion and optical methods. He is studying new optical methods for combustion diagnostics. These include methods for full-field data acquisition of temperature, concentration and velocity.