Numerical investigation of air enclosed wave impacts in a depressurised tank
Numerical investigation of air enclosed wave impacts in a depressurised tank
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DOI：
10.1016/j.oceaneng.2016.06.044
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发表时间：
2016-09
影响因子：
5
通讯作者：
Zhihua Ma;D. Causon;L. Qian;C. Mingham;P. M. Ferrer
中科院分区：
文献类型：
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作者：
Zhihua Ma;D. Causon;L. Qian;C. Mingham;P. M. Ferrer
本文使用在开源 CFD 软件中实现的可压缩多相流模型，对低填充减压晃动罐中的冲击波冲击事件进行数值研究。这项研究的主要重点是冲击罐垂直壁的水动力载荷。详细的数值解与实验结果进行了很好的比较，并证实了空气滞留的冲击波冲击导致垂直壁经历脉动压力载荷，其中在第一个施加的压力峰值之后依次出现交替的正表压和负表压。发现最强的压力脉动位于被水团捕获的气穴附近。沿垂直壁的瞬时压力分布在气穴所包含的区域中几乎是均匀的。壁上脉动压力的阶段与截留气穴的膨胀和收缩同步。水袋的形状发生变化，随水团向上移动，最终分解成小部分。仔细整合壁压力表明，整个垂直结构承受着脉动的水平冲击力。结果发现，本研究预测的脉动周期平均周期约为 5-6 ms，加载脉动在 0.1-0.2 s 内迅速衰减。对流体热力学的进一步探索性研究表明，截留气穴内的温度在大约 2 毫秒内与气穴第一次收缩同步快速上升，然后产生的热量在大约 3 毫秒内迅速转移走。
This paper presents a numerical investigation of a plunging wave impact event in a low-filling depressurised sloshing tank using a compressible multiphase flow model implemented in open-source CFD software. The main focus of this study is on the hydrodynamic loadings that impinge on the vertical wall of the tank. The detailed numerical solutions compare well with experimental results and confirm that an air trapped plunging wave impact causes the vertical wall to experience pulsating pressure loadings in which alternate positive and negative gauge pressures occur in sequence following the first applied pressure peak. The strongest pulsations of the pressure are found to be near the air pocket trapped by the water mass. The instantaneous pressure distribution along the vertical wall is nearly uniform in the area contained by the air pocket. The phases of pulsating pressures on the wall are in synchronisation with the expansion and contraction of the trapped air pocket. The pocket undergoes changes in shape, moves upwards with the water mass and eventually breaks up into small parts. A careful integration of the wall pressure reveals that the vertical structure as a whole experiences pulsating horizontal impact forces. It is found that the average period of pulsation cycles predicted in the present study is around 5–6 ms, and the loading pulsations are quickly damped out in 0.1–0.2 s. Further exploratory investigation of the fluid thermodynamics reveals that the temperature inside the trapped air pocket rises quickly for about 2 ms synchronised with the pocket's first contraction, then the generated heat is rapidly transferred away in around 3 ms.