# A Comparative Study on Violent Sloshing with Complex Baffles Using the ISPH Method
## 6 Conclusions  
The incompressible SPH method is used to simulate liquid sloshing in a tank with different configurations of the baffles, including one vertical baffle, two horizontal baffles, one vertical and one horizontal baffle, one vertical and two horizontal baffles, and one T-shape baffle. By comparison of the ISPH results with the experimental data and CFD software STAR-CCM+ computations, ISPH shows a better agreement in both the free surface profiles and the impact pressures for a sloshing tank without any baffles. Through follow-on model applications, ISPH demonstrated its great potential in predicting the fluid-structure interaction in violent sloshing flows. The main purpose of the paper is to study the practical importance of the effect. The main conclusions of the paper are as follows. Firstly, installing baffles in the sloshing tank can dampen the liquid sloshing and reduce the impact load effectively. Secondly, increasing the length of the vertical baffle in the tank is useful for dampening the liquid sloshing surfaces and reducing impact pressures. Thirdly, the submerged depth of the horizontal baffles has a great effect on the sloshing damping and the free surface is the most effective position to place the horizontal baffles. Finally, the combination of one horizontal baffle and one vertical baffle has an excellent effect on the sloshing dampening, while adding an extra horizontal baffle to the tank shows little improvement in view of dampening the sloshing load. In summary, the maximum fluid impact pressure of the sloshing system can be controlled to some extent by effectively using a well-designed complex baffle system with optimum configurations. In reality, the baffles installed in the practical sloshing tanks are usually not rigid, so the baffles with hydro-elasticity [28; 29; 30] should be further studied in future works. Moreover, the following issues should be noted as the model limitations in the present sloshing applications:  
1. Both of the ISPH and STAR-CCM+ computations have been carried out in 2D. According to previous trials, it seems that not much difference has been generated between the 2D and 3D STAR-CCM+, at least for the water surface and impact pressure in the present sloshing flows;
2. The compressibility of entrapped air should have played an important role during the violent sloshing process, and a fully two-phase ISPH coupled model would provide an ultimate solution for such a process. The maximum Mach number of all the particles in the experimental validations remains nearly below 1%, which may have partially justified the use of the incompressible SPH model;
3. Using a full 3-D model compared with a 2-D model could lead to different flow fields when the turbulence model is employed. This could partially explain the numerical disagreement between STAR-CCM+ and ISPH in the model validations. As documented by [PERSON] et al. [31], the presence of turbulence produces fully three-dimensional flow structures in the breaking region at the tip of the wave crest. In the sloshing applications, the major interest would be the general free surface deformation and macro liquid impact pressure on the tank walls. Therefore, a 2D ISPH model could provide a reasonable engineering approximation;
4. SPH for the coastal and ocean engineering problems has been mainly used for impulsive wave impact on breakwater, and similar longer simulations are often performed with the more traditional CFD methods such as VOF;
5. Lastly, the existence of baffles can indeed change the resonance frequency of a sloshing tank and this effect can be quantitatively evaluated by [2; 3; 4]. However, under the resonance frequency, some nonlinear quantities such as impact pressure may not achieve the maximum but result in a slight phase shift, which has also been observed in [20]. In the present study, we mainly used the maximum impact pressure rather than other resonance quantities.