NONLINEAR INSTABILITY OF LIQUID JETS WITH THERMOCAPILLARITY

The breakup mechanism of a capillary jet with thermocapillarity is inv estigated. Effects of the heat transfer from the liquid to the surroun ding ambient, the liquid thermal conductivity, and the temperature-dep endent surface tension coefficient on the jet instability and the form ation of satellite drops are considered. Two different disturbances ar e imposed on the jet. In the first case, the jet is exposed to a spati ally periodic ambient temperature. In addition to the thermal boundary condition, an initial surface disturbance with the same wavenumber as the thermal disturbance is also imposed on the jet. Both in-phase and out-of-phase thermal disturbances with respect to surface disturbance s are considered. For the in-phase thermal disturbances, a parameter s et is obtained at which capillary and thermocapillary effects can canc el each other and the jet attains a stable configuration. No such para meter set can be obtained when the thermocapillary flows are in the sa me direction as the capillary flows, as in the out-of-phase thermal di sturbances. In the second case, only an initial thermal disturbance is imposed on the surface of the liquid while the ambient temperature is kept spatially and temporally uniform.