Numerical investigation of full-depth double-chamber perforated caisson using the SPH method

Experimental and numerical investigation on the perforation resistance of double-layered metal shields under high-velocity impact of soft-core projectiles

Although floating breakwaters have been widely adopted, their practical deployment is constrained by significant challenges: reduced effectiveness in attenuating long-period waves. Floating breakwaters have been widely used in ocean engineering owing to their outstanding environmental adaptability. In this research work, a coupled numerical model between enhanced SPH method and mooring analysis program was established, where an Active Wave Absorption Technology (AWAS) system was used to simulate wave propagation. After that, the convergence and accuracy of the coupled model were verified systematically. Based on this, the slamming characteristics of a rectangular floating breakwater with wings were investigated, as well as its wave-attenuating performance and motion responses. The velocity fields and vortex fields for floating breakwaters with wings were also compared in detail to explore the hydrodynamic performance of the whole system. It can be found that the wave dissipation performance of a rectangular floating breakwater with wings improves by 4%–5% compared to a traditional rectangular floating breakwater, even for long-wave conditions, which can offer valuable references for optimal design of floating breakwater in the coming future.

Numerical investigation of melting process with natural convection inside multi-tube horizontal cylinder by SPH method

The present work is dedicated to the numerical investigation of sloshing flows inside a ship LNG fuel tank. Long time simulations, involving 3-hours real-time duration with realistic severe sea-state forcing, have been performed using a parallel CFD solver running for several weeks on a dedicated cluster. The numerical model adopted is the Smoothed Particle Hydrodynamics model (SPH). This model has been chosen for its Lagrangian approach and for the intrinsic properties of mass and momenta conservation which makes it well adapted for the simulation of violent free-surface flows. The adopted SPH method relies on a Riemann Solver for the calculation of the particle interactions which increases the stability of the scheme and allows for accurate predictions of the pressure during water impact stages. Three different filling height conditions are considered. For all of them energetic sloshing flows are induced with the occurrence of several water impact events. The latter are focused on specific zones of the tank depending on the considered filling height. For some conditions the SPH pressure predictions are compared with experimental ones. A critical discussion of these predictions is performed, highlighting the cases in which the numerical solver is able to provide good local pressure estimations.

The Bingham model can effectively describe the flow behavior of viscoplastic fluid. It is important to study the flow characteristics of Bingham fluid to understand the dynamic mechanism of viscous debris flow. In this study, the Bingham fluid flow on a slope is numerically researched using a corrected smooth particle hydrodynamics (CSPH) method based on periodic density re-initialization and artificial stress. First, the accuracy and stability of the improved SPH method are verified by the benchmark problem impacting droplets. Then, the flow characteristics of the Bingham fluid on the slope and the influence of the slope inclination angle on the Bingham fluid movement process are studied with the improved SPH method. The numerical results show that the improved SPH numerical scheme has higher accuracy and better stability and can deal with the complex flow behavior of the unsteady Bingham fluid.