Study of the formation mechanisms of forced expiratory wheezes in a healthy person when breathing gas mixtures of different density

The aim of the study is to specify the localization and formation mechanisms of forced expiratory wheezes (FEWs) in the bronchial tree. Statistical modeling of FEW spectral parameters has been performed, which were recorded above the lower sections of the lungs to the right and left, as well as over the trachea, from a sampling of 25 volunteers who breathed gases of different density. It was established that the highest amplitude FEWs formed closer to the trachea, and the lowest, in more distally located levels of the bronchial tree. The lower the density of the gas, the closer to the trachea the formation of mid-frequency FEWs occurs. For earlier high-frequency FEWs, an indirect dependence of their peak frequency on the Reynolds number was revealed. Turbulent-flow-induced forced oscillations and, in particular, vortex shedding are the probable formation mechanism for some of the FEWs.