Dissolution dynamics of a vertically confined sessile droplet

We experimentally investigate the dissolution of microscale sessile alcohol droplets in water under influence impermeable vertical confinement. The introduction confinement suppresses mass transport from droplet to bulk medium comparison with non-confined counterpart. Along a buoyant plume, flow visualization reveals that confined is hindered by newly identified mechanism - levitated toroidal vortex. morphological changes due vortex-induced impediment alters rate, resulting enhancement lifetime. Further, we have proposed modification key non-dimensional parameters (Rayleigh number $Ra^{'}$ (signifying buoyancy) and Sherwood $Sh^{'}$ flux)) lifetime $\tau_{c}^{'}$, based on hypothesis linearly stratified surroundings (with revised concentration difference $\Delta C^{'}$), taking into account geometry confinements. show experimental results corroborate universal scaling relations $Sh^{'} \sim Ra^{' 1/4}$ $\tau_{c}^{'} \Delta C^{'-5/4}$. also draw attention fact law incorporating confinements present work can be extended other known configurations such as inside range channel dimensions, encountered gamut applications micro-fluidic technology biomedical engineering.