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A novel mesoscopic modeling technique has been developed to simulate the unsteady growth of multiple equiaxed dendritic grains into a supercooled melt of a pure substance. In the model, the numerical calculation of the temperature field in the supercooled melt between the grains is coupled with a stagnant-film model for dendrite tip growth, such that without resolving individual dendrite arms the evolution of the grain envelope and the internal solid fraction can be predicted. The simulations are in good agreement with experiments for the growth of a single dendritic grain of the model substance succinonitrile. The model is then applied to simulate the growth of various configurations of up to 14 strongly interacting grains. The results indicate that the use of local analytical solutions in numerical calculations is a viable technique for simulating large-scale dendritic growth phenomena. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.