【作者】 李汪讳；

【导师】 宗智； 孙雷；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2010， 硕士

【摘要】 本文基于势流理论,利用边界元方法,对水下爆炸兴波及其对结构物作用问题进行了数值研究。首先,对无限水深时域格林函数进行了推导,并介绍了时域格林函数的快速算法,用于接下来的时域计算。其次,基于一种简单的气泡模型的假定(Rayleigh气泡模型)建立起水下爆炸气泡脉动的数学模型,并通过求解气泡脉动微分方程得到气泡脉动的源强。然后,在势流理论的基础上,应用满足线性自由水面条件的定常移动源时域格林函数,代入气泡脉动源强对水下爆炸兴波进行数值模拟。之后,将时域格林函数法应用于计算结构物在爆炸兴波作用下的绕射问题。本文给出了无限水深中结构物在不同频率的规则波作用下的绕射问题,并将其与频域解得的结果进行比较,由此来验证数值方法的准确性。而后用前文计算的爆炸兴波代替规则波,给出了结构物受爆炸兴波作用产生的波浪力的计算算例,并初步探讨了波浪力随炸药量、炸药埋深及结构物与爆炸源水平距离的变化规律。最后在前文工作的基础上,将爆炸兴波对固定结构物作用问题拓展到对漂浮结构物作用问题的计算。同时,本文给出了无限水深中的结构物在不同频率的规则波作用下的绕射-辐射问题,并将其与频域结果进行比较,由此来验证数值方法的准确性,并给出了结构物在爆炸兴波作用下的绕射-辐射问题的相应算例。通过对计算结果的分析总结了在爆炸兴波作用下,结构物的运动响应与炸药量、炸药埋深及结构物与爆炸源水平距离等的关系。更多还原

【Abstract】 Boundary element method based on potential flow theory has been developed to solve the waves induced by underwater explosion and their action on structures in the time domain.A fast algorithm for time-domain Green function at infinite depth and its derivatives are presented for following calculations.Next, based on the assumption of a simple bubble model (Rayleigh bubble model), bubble dynamics equations have been established for the source strength of the bubble pulsation.Water waves caused by underwater explosion have been simulated by the evaluations of time-domain Green function with the source strength replaced by the bubble pulsation on the basis of potential flow theory.Then the actions of underwater explosion induced water waves on fixed structures have been numerically analyzed. The calculation model is first examined by the diffraction of simple shape body (hemi-sphere and truncated cylinder) in regular waves. The computed wave forces are compared with the frequency-domain results, and they agree very well. The diffraction problems of fixed structures under waves caused by underwater explosion are considered next. A relationship between wave forces and explosive charge or explosive embedment depth or horizontal distance between explosive source and structures has been studied later.Finally, diffraction-radiation problems are examined in context of simple shape body (submerged sphere and floating box) and compared with the frequency-domain results. The parameter analysis of explosive charge, explosive embedment depth and horizontal distance between explosive source and structures is implemented.更多还原