Experimental invesligalion of the influence of fog formationIndices on the free convective heat and mass transfer at a vertical cooled plate D L Abstract. The influence of fog formation within the boundary RF layer on free convective heat and mass transfer at a vertical Tr cooled plate in humid air was studied experimentally. Tempera-W ture field, heat and mass transfer rates as well as thickness and co structure of the fog layer were measured. Caused by fog formation, heat transfer at lhe wall is increased and mass transfer is decreased considerably.