Marangoni-effect velocity distribution due to time-oscillatory temperature gradients in zero-gravity environment

An investigation of the uncoupled effect of a time-varying temperature field was investigated analytically to determine the oscillatory velocity fields in a cylindrically enclosed liquid undergoing Marangoni convection past a critical temperature. The study was performed in order to model the crystal growth characteristics which can be expected to occur in melts operating in a microgravity environment. Attention was given to exposure of the liquid column to axially unsteady linear, parabolic, sinusoidal, and exponential temperature changes imposed at the surface. Temperature oscillations were determined to cause an oscillatory growth speed, thereby introducing impurity striations in a forming crystal or metal. Isorotation of the float zone about its longitudinal axis is suggested to permit control of the convection pattern.