Figure 1

Jet-assisted fluid entrainment extends the aerodynamic reach of the canine nose during active sniffing.

(a) Reconstructed model of the canine nose based on the model of Craven et al.^36,38,59 (2007, 2009, 2010) that includes the nasal vestibule, external nose, lower jaw, and about 10 cm of the snout. (b,c) Images extracted from high-speed schlieren videography flow visualization with helium illustrate the directionality of the expelled air jets from anterior (b) and dorsal (c) views. (D) Visualization of theatrical fog shows the ventral-laterally directed turbulent air jets exiting the naris during expiration. (e) During the expiratory phase of sniffing, turbulent air jets vectored ventrally and laterally entrain odorant vapor from tens of centimeters ahead of the nose that would otherwise be inaccessible to the dog. (f) Schlieren image of the 3D printed dog’s nose during the inspiratory phase of sniffing showing acetone vapor be drawn into the nose from a source that is located approximately 10 cm away. (g) During the inspiratory phase of sniffing each nostril draws in air from all directions, including odorant-laden air that was drawn toward the nose during expiration. See Supplemental Information for video footage of these visualizations.