In order to shorten the computation time, the finite element method with a lower memory requirement is developed. Also, in order to improve the accuracy of the flow simulation, the apparent viscosity was measured.

The computation time of the flow simulation by the experimental program was shortened where compared with the commercial program simulation.

The apparent viscosity of castings was found to depend on the value and the geometric factor of the solid phase in the molten metal. Also, this solid phase became smaller with an increase in the molten metal velocity. Therefore, the apparent viscosity for the flow simulation of an Al-Si alloy was derived from the solid fractions and the molten metal velocity.

The molten metal flow was determined by observing the flow that depended on the distribution of the backing pressure in the cavity and the solidification state. The flow simulation of T-shaped castings based on the change in the apparent viscosity and the backing pressure was similar to the measurement.