Seasonal influenza epidemics have been responsible for causing increased economic expenditures and many deaths worldwide. Evidence exists to support the claim that the virus can be spread through the air, but the relative significance of airborne transmission has not been well defined. Particle image velocimetry (PIV) and hot‐wire anemometry (HWA) measurements were conducted at 1 m away from the mouth of human subjects to develop a model for cough flow behavior at greater distances from the mouth than were studied previously. Biological aerosol sampling was conducted to assess the risk of exposure to airborne viruses. Throughout the investigation, 77 experiments were conducted from 58 different subjects. From these subjects, 21 presented with influenza‐like illness. Of these, 12 subjects had laboratory‐confirmed respiratory infections. A model was developed for the cough centerline velocity magnitude time history. The experimental results were also used to validate computational fluid dynamics (CFD) models. The peak velocity observed at the cough jet center, averaged across all trials, was 1.2 m/s, and an average jet spread angle of θ = 24° was measured, similar to that of a steady free jet. No differences were observed in the velocity or turbulence characteristics between coughs from sick, convalescent, or healthy participants.

An experimental study of cough airflow fields produced by subjects who had influenza-like illness was conducted. Particle image velocimetry (PIV) and hot wire anemometry (HWA) measurements were taken in the far-field downstream of the mouth of a participant. Droplet sampling was performed at two locations within a large cough chamber, and a nasal swab confirmed the presence of an infection. The present work analyzes data from two separate cohorts, and modest differences were observed between coughs from sick and convalescent participants. The results are also compared to data obtained from a large eddy simulation (LES) which seeks to model the transient behaviour of a human cough.