| dc.description.abstract | Perforated plate structures are widely applied in the maritime industry, while the hydrodynamic loads on them are hard to predict. This thesis aims to explore a methodology to utilize Computational Fluid Dynamics (CFD) in combination with the experimental method to study the hydrodynamic loads on perforated plates. Following the objective, the research questions are raised: How to use CFD to predict the hydrodynamic characteristics of perforated plates? How do different perforation patterns influence the hydrodynamic characteristics? How to directly predict hydrodynamic loads on perforated plates by model tests and CFD simulation? To answer the questions, five plates with different perforation patterns were designed as the research objects, and three sub-studies were carried out.
In the first sub-study, a forced oscillation test was simulated using the commercial CFD software STAR CCM+. The numerical prediction was in good correspondence to experimental results from publications. The validated numerical simulation was then applied to the five perforated plates. It was found the nondimensional added mass and damping are negatively correlated with the perforation ratio and almost independent of the perforation spacing.
In the second sub-study, the slamming loads on perforated plates were investigated. Initially, a quasi-2D CFD model was built in STAR CCM+ to investigate the effects of different simulation setups. A visual evaluation showed that the created quasi-2D model is able to recover expected flow features during the water impact. Then, 3D CFD models were created to simulate the water impact of the five perforated plates. The results showed that the slamming impact has a negative correlation with the perforation ratio, while it is insensitive to the perforation spacing.
In the third sub-study, model tests were conducted at the wave flume of NTNU Ålesund to measure the wave loads on a fixed perforated plate. The real measured loads were then compared with the numerical results from the corresponding CFD model. The comparison showed a reasonable agreement, which demonstrated the validity of the present experimental setup and CFD model. | |