Study of Water-Entry Impact of Wedge and Ship-Like Section Using Potential Theories and CFD
- Yonghwan Kim (Seoul National University) | Kyung-Kyu Yang (Osaka University) | Jung-Hyun Kim (Seoul National University) | Zhang Zhu (Seoul National University)
- Document ID
- International Society of Offshore and Polar Engineers
- International Journal of Offshore and Polar Engineering
- Publication Date
- June 2017
- Document Type
- Journal Paper
- 168 - 176
- 2017. The International Society of Offshore and Polar Engineers
- CFD, Generalized Wagner Method, Water-entry impact, Modified Logvinovich Model
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- 60 since 2007
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This paper presents the results of potential-based methods and computational fluid dynamics (CFD) for the water-entry impact of a wedge and ship-like section. In the potential-based computation, a Generalized Wagner Model (GWM) and a Modified Logvinovich Model (MLM) were used. In the CFD computations, a constrained interpolation profile (CIP)-based method and commercial software were used for the prediction of fully nonlinear slamming phenomena. The grid convergence index for the peak pressure was analyzed for both CFD computations. The computational results were also compared with the experimental results obtained by the Korea Research Institute of Ships and Ocean Engineering (KRISO) as part of the Wave Induced Loads on Ships Joint Industry Project-III (WILS JIP-III). In the experiment, free drop tests were performed for 2-D wedges and ship sections of a containership. Accuracy was investigated in terms of the peak pressure, pressure distribution, local hydrodynamic force, and free-surface shape.
When a water wave hits a ship or offshore structure, spatially and temporally localized impact pressure is created. An accurate prediction of the impact pressure on a structure is one of the essential elements to ensure safety in the design of ships or offshore structures (Faltinsen et al., 2004). In particular, the problem of a body falling into calm water at a constant speed has been tackled on the basis of the pioneering works of von Karman (1929) and Wagner (1932). Their methods are still used through the extension of the methods to solve the problem of an arbitrary body shape, and they are called the generalized von Karman and generalized Wagner methods (Kim et al., 2007).
In many papers studying the water-entry problem, the wedge model was commonly used because of its simple geometry and similarity to the shape of engineering structures such as a seaplane landing gear and the bottom of high-speed vessels. The wedge water-entry problems have been solved through the use of theoretical (Mei et al., 1999; Korobkin, 2004; Khabakhpasheva et al., 2014), experimental (Yettou et al., 2006; Tveitnes et al., 2008), and numerical methods (Oger et al., 2006; Kim et al., 2007; Johannessen, 2012; Yang and Qiu, 2012).
|File Size||3 MB||Number of Pages||9|