Portional to mt, which is calculated by the (SST k-v) turbulence model. All air properties were assumed to be constant (rg ?1.225 kg m23, Dva ?2.545 ?1025 m2 s21) and isothermal conditions were assumed, mainly because the aim was to focus on the general transport mechanism of a passive scalar, in this case water vapour. Buoyancy effects and radiation were also notThe impact of microscopic water va