Investigation of Aerator Flow Pressure Fluctuation Using Detached Eddy Simulation with VOF Method

The detached eddy simulation model and volume of fluid (VOF) method were combined to simulate the pressure fluctuations in the downstream region of an aerator in a spillway tunnel, which often lead to hydraulic structure failure. The predictions were compared to experimental data to validate the model. Satisfactory agreement was obtained between the simulation and experimental results. The root mean square and fluctuation coefficient exhibited single-peak distribution, with the maximum values attained in the impact zone. The ranges of fluctuations of the pressure coefficient in the impact and stable zones were 3.31%-7.08% and 0.96%-3.15%, respectively. The probability density distribution obeyed a normal distribution law and presented a positive skew. The pressure fluctuation characteristics were primarily controlled by large-scale coherent eddies. The flow in the downstream region was a typical low-frequency fluctuation flow. The turbulent kinetic energy spectrum of the flow was congruent with Kolmogorov's -5/3 law. Our method is convenient for engineers to analyze pressure fluctuation characteristics and propose the shape of a hydraulic structure with superior hydraulic characteristics.