CFD modelling of a pulsed jet formed during an idealized isolated cough

Abstract

The current contribution presents the results of calculations of a pulsed jet formation during a single cough based on the recent test by Fabregat et al. (2021) where the DNS of an idealized isolated cough was performed. Two approaches for turbulence modeling were applied – the Large Eddy Simulation (LES) and the Unsteady Reynolds-Averaged Navier-Stokes (URANS). The particles propagation was described with the Lagrangian formulation, both with and without interaction with the continuous phase. Unsteady changes in the airflow structure of the pulsed jet are analyzed and discussed, with respect to the accuracy of the turbulence modeling method used. The calculated data show that during the period of 1.5 s the strong pulsed jet dissipates and transforms to a puff. By that instant, the puff front propagates over the distance of up to 0.5 m (URANS data) and 0.6 m (LES data). During the initial period, the URANS data differ from the LES data; nevertheless, at subsequent time instants, the velocity and temperature fields are similar.