Search Results (2)

The objective of the present study is to develop and validate a two-way coupling simulation method between viscous fluid and multibody dynamics to estimate the power generation performance of point absorber wave energy converters. For numerical analysis of fluid dynamics, an enhanced density correction model was proposed to improve the accuracy and stability of the pressure calculation in DualSPHysics, an open-source code based on smoothed particle hydrodynamics (SPH). Through 2D hydrostatic and wave generation simulations, it was seen that the relative error in the average pressure was reduced from 11.81% to 1.64%. In addition, an interaction interface was developed to enable coupling simulation with RecurDyn, a commercial software for the simulation of multibody dynamics. Simulations were performed for a 3D single-body cylinder with a simple shape and a two-body floating wave energy converter (WEC) in regular waves, varying the linear damping coefficient of the power take-off (PTO) system to verify the proposed coupling simulation method for fluid-multibody dynamics. The results were benchmarked against experimental data, revealing a relative error of 1.05% with the experimental results when employing a high damping coefficient for the PTO system. Furthermore, to improve the efficiency of the two-body WEC, two design modifications were suggested; their impact on power generation performance improvement was examined. The developed method is anticipated to contribute to research aiming to enhance the power generation efficiency of various wave power devices with multiple elements and joints, pending further validation and refinement of the simulation approach. Full article

Prediction of sloshing loads, which is one of the most important issues in the design of LNG carriers, has usually been carried out by experiments. When designing a 6-DOF platform equipment used for sloshing experiments, it should target a system containing a fluid, not a solid, thereby making it difficult to predict precisely the dynamic load due to the changes of a center of mass according to the tank’s movement. In the present study, two-way co-simulation technology between DualSPHysics and RecurDyn has been developed to analyze the mechanical behavior in multi-body system coupled with fluid motion; in which DualSPHysics is an open-source code based on particle method for fluid analysis and RecurDyn a commercial software for multi-flexible-body dynamics (MFBD). The developed technology was applied to the sloshing problem inside a tank connected to an upper plate on a 6-DOF platform. The simulation results were verified through comparison with the experiments conducted for this study independently, such as snapshots of flow motion, pressure on the cargo hold, and force applied to the tank-platform connection. Finally, to investigate the effects of fluid dynamic load on structural safety assessment, a two-way co-simulation between fluid-MFBD analysis was performed for two cases filling partially with fluid and solid. As a result, it was concluded that the sloshing experiment system used in this study was quite safe, and the feasibility of using the present co-simulation technology for structural safety assessment was confirmed. Full article