The impact on water of aeronautical structures is likely to turn into a tragic event. In view of this, it is essential to develop new solutions to design worthy structure that can assure best behavior. The Smoothed Particles Hydrodynamics (SPH) is a mesh-free interpolation method which is a recent numerical analysis technique. One example of water impact based on SPH is presented here, which aims at an accurate numerical simulation of Fluid-Structure Interaction(FSI) in free surface flow context. The example describes a rigid sphere impacting onto water, presenting the global impact behavior as well as comparing the impact coefficient with analytical and experimental results. The SPH method is proved to be a reliable and efficient numerical tool.

The outcomes of a research focusing on water modeling and Fluid-Structure Interaction by ALE and SPH in LSTC/LS-Dyna971 are presented in this paper. Firstly the water impact behaviors of a rigid wedge are modeled with water region by ALE and SPH. The size of fluid elements plays critical role to the numerical results, so three different cases varied in mesh or particle spacing both in ALE and SPH methods are detailed discussed. The numerical results are compared both one to the others and to the experimental and theoretical results in terms of vertical velocity and slamming force, which can be concluded that the more elements modeled in the simulation, the better approximation with the experiment results. An additional discussion of propagation of pressure wave by SPH and CPU time are also presented.

Numerical simulations of two-dimensional cylinder free droping into water are presented based on volume of fluid (VOF) method and dynamic mesh technique. Solutions with a time-accurate finite-volume method (FVM) were generated based on the unsteady compressible ensemble averaged Navier-Stokes equations for the air and the unsteady incompressible ensemble averaged Navier-Stokes equations for the water. Computed pressure histories of the cylinder were compared with experimentally measured values. The performance of various turbulence models for pressure prediction was assessed. The results indicate that Realizable k-epsilon model with Enhanced Wall Treatment is the best choice for engineering practice.

Based on the characteristics of blowing control, a new technique was put forward to weaken slat cove separation and reduce noise. The effect of the slat blowing control on lift performance, the flow field and noise with a three-element high lift aerofoil was investigated by using the computational fluid dynamics (CFD) code of Fluent and the Reynolds-averaged Navier-Stokes equations. The blowing apertures were set on the lower surface of the slat. By using the slat blowing technique, the slat cove separation can be controlled efficiently and the lift coefficient increased. The aerodynamic performance varies with different blowing flow rates and angles of attack.