Characterizing airborne odor landscapes using simultaneous stereo PIV and PLIF

Animals rely on odors to survive, navigating chaotic plumes for critical tasks like finding food, mates, and habitat. Recent research on olfactory navigation shows the importance of multimodal sensing, that is, simultaneous processing of the chemical signals from the odor as well as the mechanical signals from the flow. However, little data exists on the co-evolution of concentration and flow signals throughout airborne odor plumes, in large part due to the experimental challenges of obtaining time-resolved data for simultaneous velocity and concentration fields in a gaseous environment. The current work employs synchronous PLIF and stereo PIV for quantitative measurements of the flow and odor fields for several configurations of naturalistic airborne plumes. Resulting datasets offer simultaneous velocity and concentration measurements over a 30 x 30 cm field of view at a temporal resolution up to 20 Hz. A recirculating wind tunnel generates the flow at speeds of 10, 15, and 20 cm/s, with a classical turbulence grid to induce chaotic behavior. To measure velocity, a 532 nm double-pulse Nd:YAG laser illuminates seeding particles, imaged by two sCMOS cameras to resolve three components of velocity. To measure concentration, a 266 nm single-pulse Nd:YAG laser excites acetone florescence (an odor surrogate), imaged by a sCMOS camera. The experiments result in rich datasets of naturalistic odor plumes as well as key statistics that yield insights into passive scalar mixing in low-Re, low-Sc gaseous plumes.