Studies were carried out in clear, elastic, cast replicas of the normal human airway system (from the mouth to subsegmental bronchi) to determine the fluid dynamic parameters pertinent to aerosol transport and deposition. The velocity organizations (local magnitude and directions), pressures (dynamic and static), and flow instabilities were measured and compared to theoretical predictions.
Olson DE, Sudlow MF, Horsfield K, Filley GF. Convective Patterns of Flow During Inspiration. Arch Intern Med. 1973;131(1):51-57. doi:10.1001/archinte.1973.00320070047005