On Particle Image Velocimetry (PIV) measurements in the breathing zone of a thermal breathing manikin

A time-resolved PIV system has been employed to obtain quantitative velocity vectors in the breathing zone (nose only) of a thermal manikin that is placed within an Indoor Air Flow-field Laboratory (IAFL). Phase averaged (with breathing cycle) velocity measurements are taken in a vertical plane down the center of the manikin face. During exhalation, an interaction between the shear layers of the air jets from the nose and the buoyant flow created by the thermal plume of the manikin is observed. A threefold increase in local turbulence intensity was found during the exhale part of the breathing waveform when compared to ambient values in the laboratory (when there was no breathing) and to the results of other studies. These results suggest that the unsteadiness associated with the breathing cycle is critical for quantifying human exposure to pollutants indoors and the associated health risk as well as for validating CFD.