A study of directional solidification of a weak binary alloy (specifically, Bi - 1 at% Sn) based on the fixed grid single domain approach is being undertaken. The enthalpy method is used to solve for the temperature field over the computational domain including both the solid and liquid phases; latent heat evolution is treated with the aid of an effective specific heat coefficient. A source term accounting for the release of solute into the liquid during solidification has been incorporated into the solute transport equation. The vorticity-stream function formulation is used to describe thermosolutal convection in the liquid region. In this paper we numerically investigate the effects of g-jitter on directional solidification. A background gravity of 1 micro-g has been assumed, and new results for the effects of periodic disturbances over a range of amplitudes and frequencies on solute field and segregation have been presented.Benjapiyaporn, C. and Timchenko, V. and Leonardi, E. and deVahlDavis, G. and deGroh, H. C., IIIGlenn Research CenterGRAVITATION; AEROSPACE ENVIRONMENTS; DIRECTIONAL SOLIDIFICATION (CRYSTALS); VORTICITY; SOLID PHASES; BINARY ALLOYS; TEMPERATURE DISTRIBUTION; CONVECTION; LATENT HEAT...