On the usefulness of bilateral comparison to tracking turbulent chemical odor plumes

Abstract

This article reports on the usefulness of bilateral comparison of chemosensory information to an animal or agent tracking an odor to its source. Instantaneous concentration fields of a chemical plume diffusing in a fully developed, turbulent, open channel flow are measured using planar laser-induced fluorescence. The plume is released isokinetically 25 mm above the smooth bed (z+ = 90), thus transport is mainly due to advection and ambient turbulence. A spatial cross-correlation function in the spanwise direction gives a strong indication of the relative position of the centerline and distance from the source. The relative direction of the plume centerline can be estimated from the instantaneous concentration, provided the sensors are separated by a distance larger than the spanwise integral length scale of the concentration field.