Fluid-Solid Interaction Simulation Analysis On Water Impact Of Structures

Fluid-solid interaction problem is widespread nature of the physical phenomena, and it has various forms. In this paper, a lot of literature is refered to, and the concept of fluid-solid interaction, classification and the research progress in the field are introduced.This article focus on structure into water which is a typical problem of fluid-solid interaction. First of all, three analytical methods are introduced in this paper: classical methods, experimental methods and numerical methods. In those methods, the ALE algorithm of numerical methods is focused on. This algorithm has the expertise of both Lagrange methods and Euler methods, that is, in the handling of border movement, it introduced the characteristics of Lagrange method, so it can effectively track the movement of the border; in the division on the flow grid, it has absorbed Euler methods' advantage, so that the flow grid unit is independent of the material entity exists, but it is different from Euler grid because the grid can be adjusted position appropriately with the defined parameters in the process of solving, making grid not to be a serious distortion. This method is very favorable with large deformation in the issue, as it can handle the issues that the whole object has a large space displacement and has large deformation itself.In the basis of the ALE algorithm, LS-DYNA was applied to analyze to the model, and the relevant results were abtained. Numerical models consists of three parts: water, air and wedge-shaped structure. Water and air are modeled with Euler grid. Wdge-shaped structure is modeled with Lagrangian grid. 3D SOLID 164 is used with water and air units. Thin Shell 163 is used with thin plate unit. In this paper, typical wedge-shaped structure is used, and the structure into water problem of different materials, different speed, different angles and different shapes are analysised detailedly. In this paper, the deformation of the process, the changes of the stress and the changes of the flow flied in the process of structure into water are given. The extent of free vibration is large in the process of structure into water, and the stress and strain field of the structure reach the maximum in an instant into the water, and then show oscillation changes. The velocity of the flow field makes the point of the structure into water as the centre of a circle, the extent of the changes in the flow field is larger when farther from the point of the structure into water. Through comparative and analysis, it can got that the deformation is larger when the velocity is greater, the thickness of the board is smaller, and the angle into water is smaller, while the deformation and the force of the structure will be greatly affected with different materials. On this basis, the process into water of the spherical objects, sealed and not sealed flat objects and the large-size objects into the water is analysised and discussed. It's compared with the process of wedge-shaped body into water, and the characteristics of these objects into water obtained.