Twi-Fluid Model Approach for Transient Analysis of Free-Surface-Pressurized Flows

摘要

A new computational model is developed here to analyze the influence of entrapped air on free- surface-pressurized flows. A virtual slot with ceiling on the top of the pipe is introduced to treat a separated gas-liquid flow. This model is a modified model of Preissmann's and is applicable not only to open channel flow and closed conduit flow but also pressurized flow with entrapped air. Compared to experimental results using the model of 1/50 scale, the calculation results show that the entrapped air in horizontal pipe advances the time of pressure rising and makes the maximum value of pressure higher.