Study On Hydrodynamic Characteristics Of Viscous Damping Model Of Open-hole Floating Cylindrical Structure

When the existing wave radiation diffraction theory is used to solve the motion response equation of underwater aperture structure,the geometric model of underwater aperture structure is first established,and the corresponding boundary integral equation is established by applying wave radiation,diffraction theory and boundary element method to solve the motion response equation of underwater aperture structure.It is found that the influence of fluid viscous damping in the motion response of the open structure cannot be ignored.Taking this as a starting point,this study used the developed wave numerical flume method to generate incident waves,and realized the forced motion fluid-structure coupling analysis of the perforated structure through FLUENT UDF function,and finally obtained the viscous damping coefficient in the motion response equation.It is found that the viscous force of the fluid is mainly concentrated near the wall surface of the structure,and the thickness of the hole structure has an effect on the viscosity coefficient.The viscosity coefficient of the hole-opening structure in the direction of heave and surge is about1.10?10^-2,and the viscosity coefficient of the hole-opening structure in the direction of roll is about2.80?10^-2?The surge,heave and roll of the open-hole structure caused obvious disturbance to the fluid in the wave flume,and the disturbance to the flow field in the upper part of the open-hole structure was relatively large.On both sides of the structure,The wave elimination effect is obvious on both sides of the structure,and the circumfluence phenomenon occurs in the local area,which has an important influence on the velocity distribution of the fluid.In the surge movement of the structure,the velocity of flow field around the structure is small,and there is an obvious phenomenon of flow around the bottom of the structure but the velocity of the surge movement flow field is larger than that of the heave flow field.Under the rolling motion,the velocity component in the surge direction is obviously larger than that in the heave direction.