Abstract
This chapter provides detailed examples of thermo-gravitational, thermo-capillary
and thermo-solutal instabilities. When a fluid is confined and in normal Earth
gravity, the fluid configuration is vertically anti-symmetric. If suddenly exposed to
weightlessness, the fluid will transition to a symmetric configuration over a period
of time. Thermo-capillary instabilities have been observed during sessile droplet
evaporation in the absence of buoyancy-driven convection and radiation. When the
droplet rests on a thermally insulating substrate, no thermo-capillary convection is
measured. However, if the substrate is thermally conductive, a transition to
thermo-capillary flow has been observed and the transition depends on the evapo-
ration rate. When a droplet evaporates into multicomponent atmospheres, thermo-
solutal instabilities arise if one of the atmosphere species has a heat of solution
with the droplet component. The thermo-solutal instabilities appear as temperature
and pressure pulsations in the liquid and in the vapor phases that are coupled by
the evaporation flux.