We have developed a mathematical model and an accompanying computer program for the computational simulation of an unsteady laminar flow of an incompressible fluid undergoing solidification. An extended Boussinesq approximation allowing for temperature-dependent physical properties of the fluid was used. Latent heat of phase change was incorporated via an enthalpy method. A single computer code thus simultaneously predicts unsteady velocity, pressure and temperature fields in the thermally buoyant melt while capturing the advancing solid front. The same code can simulate the reverse process of unsteady thawing or melting of the solid phase.
