What is the best frequency for sniffing?*

Mammals such as dogs are known for their keen sense of smell and have been relied upon for their ability to find odor sources. A key component to the mammalian sense of smell is the dynamic sniff cycle which increases in frequency when then animal is exposed to a new odor. Conversely, we find through oscillatory wind tunnel experiments and computational simulations that lower sniffing frequencies provide better odor collection in straight, rectangular channels. Lower sniffing frequencies reduce velocities near the channel walls, enabling a larger number of odor molecules to reach receptors via diffusion. We proceed from rectangular channels to investigating the effect of biological nasal cavity shapes helps to mitigate odor collection.  We apply insights gleaned from our biological and experimental results to design an electronic nose pre-concentrator for improved chemical sensing.