Hydroelastic Analysis Of Structures Water Entry

Water entry slamming is a complicated hydroelastic problem,which is paid more and more attention in the field of naval architecture and ocean engineering.A comprehensive review of the state of the art and the tendency for future advances in the field of water entry of structure is presented in this thesis.A systematic study on the process of water entry slamming is performed based on hydrodynamics,structural mechanics and hydroelasticity theory and with the aid of ANSYS numerical simulation software and model test technology.The main research work and major results in the present thesis are as follows:(1)The mathematical model of fluid and structure interaction for the study of water entry slamming is established based on hydrodynamics,structural mechanics and hydroelasticity theory.The mathematical model includes continuous equation of fluid,N-S equations,structural dynamic equations and boundary conditions.(2)Numerical simulation for two-dimensional rigid wedge water entry is performed.The influence of the height of the dropping and the shape of structure on the water entry is analyzed.The results show that the greater the height of the dropping is,the larger the cavitation area produced at the top of the wedge is and the greater the perturbation field is.And it also brings more energy losing.When reducing inclination of the wedge,it may increase instantaneous impact.(3)Water entry is simulated for a three-dimensional rigid wedge.The comparison shows the difference between 2D and 3D rigid wedge water entry.The effect of the cone angle of rigid wedges on the water entry is analyzed.The results show that with the increase of the angle,the starting point of water entry moves reward and the slamming is decreasing.(4)Based on the results of the numerical simulation,a reduced scale structure model and test device are designed.The slamming pressure during the structure water entry is measured in real time through the sensors arranged on the wedge structure.The effective and feasibility of the numerical simulation method is validated by model test.(5)Numerical simulations of water entry for 3D rigid and flexible wedge are conducted.The hydroelastic city of flexible structure is analyzed,which is compared to the rigid structure.By the contours of pressure and the curves of the pressure of the monitors,the conclusion is drawn: at the same condition,the pressure of flexible structure is less than that of rigid structure.