We have investigated the capabilities of modern numerical methods for the prediction of the melt/crystal interface geometry during encapsulated GaAs Czochralski growth with the vapor pressure control. Using an advanced Navier-Stokes solver, characteristics of 3D unsteady melt turbulent convection are studied for real growth regimes and the results are compared with the data by the conventional 2D steady approach. The effect of radiative heat exchange in the encapsulant is estimated with respect to its influence on the crystallization front geometry. The analysis is performed using experimental data for the growth of 3- and 4-inch GaAs crystals. (C) 2004 Elsevier B.V. All rights reserved.