SPH simulation of cylinder and wedge water entries.

Abstract

Smoothed particle hydrodynamics (SPH) is a numerical approach applied meshless Lagrangian method in the fluid study, which is different from the common computational fluid dynamics (CFD) on the basis of the Eulerian description. Compared with the traditional experiement studies, the numerical approaches provide much simpler way in simulating fluid behaviors, and the results are also considered to be reliable and accurate. Therefore, the numerical approaches are playing a more and more important role with the support of the fast developing computer technology nowadays.

In this thesis, the water impact simulations are made in the DualSPHysics, which is a numerical program based on the SPH method. Four cases are simulated: water entries of both two- and three-dimensional horizontal cylinders with the constant velocities, free falling of two-dimensional cylinders, and water entries of two-dimensional wedges with various deadrise angles. The results of simulations in DualSPHysics are evaluated through the comparison with previous theoretical analyses, experiments and other similar numerical simulations, also the influences of the parameter settings in the program are discussed. The emphasis is on the vertical hydrodynamic forces and slamming coefficients at the slamming moments.

Most of the results are encouraging, with good agreement with the previous works, but the computing accuracy is limited by the capability of the computer. It is believed that more appropriate parameters can be applied in powerful computers, and better results can be expected as well.