Flow Structure around Pneumatic Flap Gate in Dry Dock during Floating Process

Stability of pneumatic flap gate in floating and submerging state in a built dockyard is greatly influenced by hydrodynamic forces acting on the gate.Based on RANS equations combined with RNG k-e turbulence closure and by using VOF method for tracking free surface,flow characteristics of dock gate are investigated in floating or flapping state and under three water levels.After comparing the data of model test with that of calculation,the flow structure around pneumatic flap gates is simulated.The results indicate that turbulent kinetic energy focuses mainly on the nearby area of hinged support,top of the front panel and the back gate angle,along with the quick development of clockwise and counterclockwise vortexes.With the elevation of water level,not only increases the turbulent kinetic energy at the three places,but also the range of eddy expands greatly,especially at underwater operation stage and closing stage.That will produce strong scouring effect on gate pit near hinged support.