A stochastic model has been developed to simulate the "natural flow" and the spatial evolution of flow patterns in the downstream direction in randomly packed beds. The natural flow is defined as the tendency of liquids flowing down a packed bed to redistribute radially in a natural fashion. A column of 0.5 m diameter with 25 mm Pall rings is selected to test the model. The simulation results of flow distributions are in good agreement with available experimental data from the literature. Unlike the existing models, our approach can simulate liquid flow distributions for different realizations of random packings.