CFD simulations of wave–current-body interactions including greenwater and wet deck slamming
CFD simulations of wave–current-body interactions including greenwater and wet deck slamming
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DOI：
10.1016/j.compfluid.2008.01.026
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发表时间：
2009-05
影响因子：
2.8
通讯作者：
Hamn-Ching Chen;Kai Yu
中科院分区：
文献类型：
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作者：
Hamn-Ching Chen;Kai Yu
求解非定常纳维-斯托克斯方程的数值方法与界面保持水平集方法相结合，用于模拟绿水对海上结构和船舶的影响。在该方法中，自由表面流被建模为不混溶的空气-水两相流，自由表面本身由零水平集函数表示。水流和气流的纳维-斯托克斯方程在移动曲线坐标系中制定，并在非交错多块网格系统上使用有限解析方法进行离散化。大涡模拟 (LES) 方法与 Smagorinsky 模型结合使用来解释剧烈的自由表面运动引起的湍流效应。嵌合域分解方法是使用重叠、嵌入或匹配网格来实现的，以促进围绕实际配置的复杂流程的模拟。重叠网格系统还大大简化了各种计算模块之间任意平移和旋转运动的模拟。首先对涉及剧烈自由表面运动的溃坝流和自由射流问题进行了计算。然后采用水平集纳维-斯托克斯方法来模拟半球的撞击、近海结构和船舶上的绿水以及 X-Craft 在纵摇和升沉运动中的湿甲板撞击。数值结果清楚地证明了水平集方法处理涉及破碎波、水滴、捕获气泡和波-流-体相互作用的剧烈自由表面流的能力。
A numerical method for the solution of unsteady Navier–Stokes equations has been employed in conjunction with an interface-preserving level-set method for the simulation of greenwater effect on offshore structures and ships. In this method, the free surface flows are modeled as immiscible air–water two-phase flows and the free surface itself is represented by the zero level-set function. The Navier–Stokes equations for both the water and air flows are formulated in moving curvilinear coordinate system and discretized using the finite-analytic method on a non-staggered multi-block grid system. Large eddy simulation (LES) approach is used with Smagorinsky model to account for the effects of turbulence induced by violent free surface motions. A chimera domain decomposition approach is implemented using overlapping, embedding, or matching grids to facilitate the simulation of complex flow around practical configurations. The overset grid system also greatly simplified the simulation of arbitrary translational and rotational motions among various computational blocks. Calculations were performed first for dam-breaking flow and free jet problems involving violent free surface motions. The level-set Navier–Stokes method was then employed for the simulation of slamming of a hemisphere, greenwater on offshore structure and ships, and wet deck slamming of an X-Craft in pitch and heave motions. The numerical results clearly demonstrated the capability of the level-set method to deal with violent free surface flows involving breaking waves, water droplets, trapped air bubbles, and wave–current-body interactions.