CFD Investigation of Regular Wave Forces on Pile Group Foundation in China-Maldives Friendship Bridge
- Ningbo Gao (Shanghai Jiao Tong University) | Hong Zhang (Shanghai Jiao Tong University) | Jianmin Yang (Shanghai Jiao Tong University) | Yongtao Zhang (Shanghai Jiao Tong University)
- Document ID
- International Society of Offshore and Polar Engineers
- The 28th International Ocean and Polar Engineering Conference, 10-15 June, Sapporo, Japan
- Publication Date
- Document Type
- Conference Paper
- 2018. International Society of Offshore and Polar Engineers
- swell, numerical wave tank, pile group foundation, wave forces
- 1 in the last 30 days
- 15 since 2007
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Wave forces and flow field around pile group foundation in China-Maldives Friendship Bridge are investigated with a Computational Fluid Dynamics (CFD) model. A numerical wave tank is developed based on the commercial finite volume package FLUENT. Mesh sensitivities are conducted to validate the numerical model, and an acceptable time-step is adopted to ensure stability in time-marching. Swells are very common in the location of the Bridge, thus in this manuscript, regular waves are simulated acting as swells. The wave interaction with single pile and pile group foundation is studied. The numerically calculated wave forces agree quite well with the predictions from Morison equation. The wave period shows minor influence on the values of maximum wave forces under the condition that the wave amplitude is unchanged. For the pile group foundation, the wave forces on piles of different locations have phase differences due to that the time of wave crest crossing the piles is different. This numerical study confirms that wave height is the key parameter for wave forces on pile group foundation in swell environment.
With the development of economic society, the construction of long-span cross-sea bridges has become much more significant around the whole world, such as HongKong-Zhuhai-Macao Bridge. Pile-slab structures are commonly used in the support structures of cross-sea bridges, offshore wind turbines and other near shore coastal structures. It is of great significance to have a thorough understanding about wave interaction with these structures.
Model test is one of the most common approaches to study the wave-structure interaction problems. The advantage of this method is that the real hydrodynamics of wave-structure interaction can be simulated directly, although physical test is limited by scale restrictions. To overcome this, analytical methods have been developed. In the case of circular cylinder structures, wave forces on these compact structures are divided into two parts: inertia forces and drag forces (Morison et al., 1950). The contribution of inertia and drag forces are determined by the number and diffraction parameter which is the ratio of the cylinder diameter (D) to the incident wave length (λ). When the number is smaller than 2 and the diffraction parameter (D/L > 0.2), the flow field is inertia dominated and wave diffraction effects are important (Sarpkaya et al., 1981). The analytical methods depend on flow coefficients that have to be estimated from experiment data, and it is limited in a small range of structures, such as circular structures.
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