Atmospheric air always contains a certain amount of water vapour being an element of the Earth's hydrological cycle. This content, which can be defined by relative humidity for example, has a significant impact on the transonic flow field. What happens then is the water vapour rapid condensation, due to a non-equilibrium process of spontaneous condensation, followed by evaporation of the resulting liquid phase on shock waves arising in a transonic flow. These two phenomena, related to the moist air flow and the heat transfer between the gaseous and the liquid phase on the condensation wave and on the shock wave, are analysed numerically and experimentally. The analyses were conducted using in-house numerical methods and an in-house experimental facility for testing transonic flows. The investigations focused mainly on geometries of convergent-divergent nozzles, which best represent transonic, i.e. subsonic and supersonic, flows. (C) 2017 Elsevier Ltd. All rights reserved.