Diffusion Fails to Make a Stink

TL;DR

This paper investigates whether simple diffusion models can explain natural scent tracking behaviors, concluding that they cannot and highlighting the importance of fluid dynamics and turbulence in odor dispersal.

Contribution

It demonstrates that purely diffusive models are insufficient for scent tracking, emphasizing the need for fluid dynamic modeling including turbulence effects.

Findings

Pure diffusion cannot satisfy scent tracking thresholds.

Fluid dynamics and turbulence are essential for accurate odor dispersal modeling.

Diffusive models fail within experimentally observed parameter ranges.

Abstract

In this work we consider the question of whether a simple diffusive model can explain the scent tracking behaviours found in nature. For this behaviour to occur, both the concentration of a scent and its gradient must be above some threshold. Applying these conditions to the solutions of various diffusion equations, we find that a purely diffusive model cannot simultaneously satisfy the tracking conditions when parameters are in the experimentally observed range. This demonstrates the necessity of modelling odor dispersal with full fluid dynamics, where non-linear phenomena such as turbulence play a critical role.