Numerical simulation of the water slamming process by the CFD-DEM-IBM approach

Abstract:

To overcome the significant challenges to accurate numerical simulations of water entry problems, like the treatment of the moving boundaries, the description of highly distorting free water surface and the reflection of strong coupling effect between fluid and solids, a CFD-DEM-IBM approach, which incorporates the computational fluid dynamics-discrete element method (CFD-DEM), the immersed boundary method (IBM) and the improved conservation level set (ICLS) method, is proposed for the precise prediction of water entry phenomenon. Fixed Cartesian grids are used to discretize the computational domain, with CFD and DEM used to describe the motion of fluid and the motion of solid bodies, respectively. IBM is introduced to track the solid boundaries and obtain accurate fluid-solid interaction forces. The free water surface is captured using the ICLS method which can ensure both the validity of interface properties and the conservation of mass. A partitioning algorithm is employed to perform multiple alternating iterations within a time step to reflect the strong coupling effect between fluid and solid, establishing a high-resolution CFD-DEM-IBM numerical model. Water entry of a cylinder with prescribed motion, symmetric and asymmetric water entry of a wedge and water entry of multiple bodies are then performed. The results show that the detailed resolution of the fluid phase along with the strong coupling effect can be reasonably reflected by the CFD-DEM-IBM approach, and it is remarkable in addressing water entry problems even when multiple rigid bodies are involved.