Flow dynamic of human cough and measuring techniques: A review

Coughing is one of the most important respiratory activities for air transmitted pathogens. It is essential to understand the dispersion of exhaled particles when coughing to improve the prevention measure and reduce the cross-infection risk. However, cough flow structure is complex and influenced by many parameters. Simplifications are often made to the initial flow condition when simulating the transport of particles expelled during coughing in laboratory or numerical studies . This study conducts a systematic literature review on human cough, especially focusing on flow dynamic characterization. First, the measuring techniques for identifying the airflow characteristic are summarized. The boundary conditions for cough, such as flow profile, flow direction, cough duration and are compared between different studies. Finally, the vortex structure of cough and its impact on cough particle dispersion is discussed.