Research On The Hydrodynamic Characters Of The Cave-in Cavity

The structure of cave-in cavities are applied in the field of aviation,navigation,harbor,channel and hydrodynamic engineering and so on. Such as the wheel storage well on the undercarriage of the airplane,the bomb-dropping cabin of the airplane for battle,the discharge orifice on the ship,the liquid storage system in the pipage. And the representative flow pattern in the cavity is also very valuable in the field of harbor,coast and offshore engineering. Such as the circumfluence motion which is existed by the outlet area of the inland harbor basins,the lock approach the caecum river reach and so on. It is obvious that the representative flow pattern of liquid in the cavity is existed universally. Furthermore, it has representative meaning for the research of eddy structure. When the liquid flow through the cavity mouth, the pressure distribution at the cavity mouth and vibration condition are the hydrokinetics problems which are studied frequently. The liquid in the cavity represent strong non-linearity and randomicity. The flow noise will be produced by the cavity mouth. The vibration respond of the cavity local structure will be generated by the fluctuating force of liquid. Therefore, it has very important engineering meaning and academic meaning for developing the research of the hydrodynamic characters and the vibration characters at the cavity mouth of the cavity structure.In this paper, the compared analysis method is used between numerical simulation and physical experiment. The hydrodynamic characters of the cavity,the vibration frequency characters of shear layer and the moving frequency characters of vortex in the cavity are studied at different Reynolds numbers,different attack angles,different cavity shapes and mass exchange. And the precision of the numerical simulation is validated by physical experiment. The research work is summarized as follows:(1) The numerical model was chosen in the numerical experiment. The sizes of fluid field were chosen and the sizes of grid were optimized. The boundary and initial conditions are decided. And the measure points layout of different cavity shapes are determined by the numerical simulation firstly.(2) Under the condition of uniform fluid, the three-dimension characters of the vortex in different cavities is researched by numerical simulation, comparing the different liquid phenomenon in different cavities. The pressure coefficients distribution along the circumferential direction at different section of the cavity are discussed and the hydrodynamic experiential formula are presented preliminarily.(3) Under the condition of uniform fluid, the influence of the hydrodynamic characters of the cavity is discussed when the mass exchange is existed in the cavity, including the three-dimension characters of the vortex in the cavity,the trend of the static and the fluctuating pressure coefficients distribution along the circumferential direction and the vibration frequency characters of the shear layer. And the hydrodynamic experiential formula are modified.(4) Under the condition of uniform fluid, the vibration frequency characters of the shear layer and the moving frequency characters of vortex in different cavities are discussed. And the influence of the vibration frequency of the shear layer is studied when the mass transfer is existed in the cavity and the regularity of strouhal numbers are summarized.(5) For validating the precision of numerical experiment, the results were compared with physical experiment results. And the advantage and disadvantage were analyzed, and the improved methods were brought forward.