Heat and mass transfer in annular liquid jets: II. g-jitter

The e€ects of g-jitter on heat and mass transfer in underpressurized, annular liquid jets are analyzed numerically as a function of the amplitude and frequency of the gravitational modulation by means of a mapping technique that transforms the timedependent geometry of these jets into a unit square and a conservative ®nite di€erence method. It is shown that the pressure coecient, gas concentration at the jet's inner interface, heat ̄uxes at the jet's inner and outer interfaces and interfacial temperature are periodic functions of time whose amplitudes increase as the amplitude of the g-jitter is increased, but decrease as the jitter frequency is increased. The pressure coecient is almost in phase with the heat ̄ux at the jet's outer interface, and out of phase with the mass transfer rate at the jet's inner interface. It is also shown that the temperature ®eld adapts itself rapidly to the imposed gravity modulation, and thermal equilibrium is reached quickly. However, mass transfer phenomena are very slow and require a very long time to become periodic. Ó 2000 Elsevier Science Inc. All rights reserved.