On the variation of fricative airflow dynamics with vocal tract geometry and speech loudness

Amir A. Mofakham, Brian T. Helenbrook, Byron D. Erath, Andrea R. Ferro, Tanvir Ahmed, Deborah M. Brown, Goodarz Ahmadi

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Recent studies have determined that the number of respiratory droplets expelled during a short duration of speech can be comparable to that of a cough. Although speaking is typically modeled as a horizontal jet, recent experimental work has shown that there are large angular variations when fricative sounds are produced. To investigate this, two-dimensional vocal tract geometries for a labiodental fricative, [f] and a dental fricative, (Formula presented.) were constructed based on magnetic resonance imaging (MRI) during these intonations. Two-dimensional ANSYS-Fluent simulations were performed to investigate the expiratory airflow from the geometries, which showed chaotic unsteady airflow trajectories with maximum velocities ranging from 20 to 40 m/s and jet trajectory angles varying between (Formula presented.) The simulations highlight the variabilities of the expirated airflow trajectories as a function of the type of utterance, speech loudness, size of the mouth opening, and tongue shape.

Original languageEnglish (US)
Pages (from-to)446-460
Number of pages15
JournalAerosol Science and Technology
Issue number5
StatePublished - 2022
Externally publishedYes


  • Yannis Drossinos

ASJC Scopus subject areas

  • Environmental Chemistry
  • Materials Science(all)
  • Pollution


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