The interfering models are represented to decide the rate of the dividing or combining at the junction of the combination pipe. In the conventional theory of the energy loss, it is all but impossible to determine the flow ratio of any ramifications, because the energy loss is a result of distribution of flux of flow and is not a cause of it. In the interfering model, the rate and the pressure
... [Show full abstract] distribution at the junction are determined by using coefficcients depending only on the geometrical scheme of the junction. Coefficients of interference are determined by the fitting method using the experimental data of the conventional energy loss coefficients. Rate calculated by using the interfering model are in accord with the well-known experimental results. Through the consideration about the case of simple network, it is shown that the rate calculated by the model coincide with the result of the Hardy-Cross method in the case of long length piping.