Study On Hydrodynamic And Flow Noise Characteristics Of Flow Around Rectangular Cylinder

The inlet and outlet of the seawater circulating cooling system are directly connected to the seawater.When the seawater flows through the inlet grille,it will produce complex flow phenomena such as shear layer separation and vortex shedding,which induces fluid pressure pulsation in the tube and flow noise.For the specific form of the actual ship installation grille,the research object is simplified into a single rectangular cylinder and rectangular cylinders arranged side by side.The main contents include the following aspects.1?The turbulence model is commonly used for numerical simulation of flow around rectangular cylinder,and the effects of grid density and time-discrete size are considered.The calculation results are compared with the previous literature data,and the meshing and numerical simulation methods suitable for this paper are selected.It is finally determined that the SST k-? turbulence model is used to calculate the unsteady flow field around the square column,and the flow noise is solved based on the FW-H equation.2?Taking the 2D single rectangular cylinder as the research object,the influence of Reynolds number,section length to width ratio and the flow field wall on the main flow parameters,pressure fluctuation distribution of the flow field and the flow noise distribution law are analyzed.The amplitude of pressure fluctuation at monitoring point is calculated by python,and the flow parameters and pressure fluctuation are transformed by fast Fourier transform.The spectral characteristics of vortex frequency,pressure fluctuation and noise and their relationship are analyzed.3?Based on the research of flow around rectangular cylinder,five 2D rectangular cylinders arranged side by side is taken as the research object.the effects of Reynolds number and rectangular cylinder spacing ratio on the flow parameters,pressure pulsation and flow noise characteristics are analyzed.4?3D numerical simulation of some working conditions of 2D numerical simulation is carried out.The difference between the 2D and 3D numerical simulation results of the flow around a single rectangular cylinder in an infinite flow field is analyzed.The difference between the 3D numerical results of the flow around a single rectangular cylinder in a circular tube and the 2D numerical results of flow around a single rectangular cylinder in a finite field is compared.