Oseen子边界元法在粘性流─固耦合运动中的应用(英文)

本文提出了一种处理二维粘性流场与扁薄弹性体相互作用的粘性流边界元理论和方法，类似于势流理论中的边界元方法，在弹性体湿表面分布Ｏｓｅｅｎ方程的基本解，即Ｏｓｅｅｎ子，并由物面边界条件确定其强度。探讨提高Ｏｓｅｅｎ方程适用雷诺数范围的问题。通过一悬臂水翼在粘性绕流流场中的振动来演示该方法的应用。

二维Oseen流中潜体产生的非定常表面波(英文)

The two-dimensional unsteady free-surface waves due to a submerged body moving in an incompressible viscous fluid of infinite depth is considered.The disturbed flow is governed by the unsteadyOseen equations with the kinematic and dynamic boundary conditions linearized for the free-surface waves.Accordingly, the body is mathematically simulated by an Oseenlet with a periodically oscillating strength.By means of Fourier transforms,the exact solution for the free-surface waves is expressed by an integral with a complex dispersion function, which explicitly shows that the wave dynamics is characterized by a Reynolds number and a Strouhal number.By applying Lighthill's theorem, asymptotic representations are derived for the far-field waves with a sub-critical and a super-critical Strouhal number. It is found that the generated waves due to the oscillating Oseenlet consist of the steady-state and transient responses. For the viscous flow with a sub-critical Strouhal number, there exist four waves: three propagate downstream while one propagates upstream.However, for the viscous flow with a super-critical Strouhal number, there exist two waves only,which propagate downstream.

自由表面与粘性尾迹的相互作用

解析地研究了无限深不可压粘性流体中运动物体产生层流尾迹与自由表面波的相互作用· 以定常的Oseen方程模拟受扰流动,对于小振幅自由表面波则采用线性化的运动学和动力学边界条件· 在数学描述上,运动物体以Oseen极子模拟,受扰流场分解成表述粘性尾迹的无界奇异Oseen流和描述自由面效应的有界正则Oseen流之和· 通过积分变换法,得到自由表面波的精确解· 借助Lighthill的两步格式。

紊流场中水翼的涡激振动分析

本文提出一种新的置于船尾流中水翼涡激振动的数值模拟方法，以湍流粘性系数代替运动粘性系数，将Ｏｓｅｅｎ奇异子片分布在二维水翼型线上，取Ｏｓｅｅｎ奇异子边界元法解作为ＮＳ方程的迭代初值，这种方法使得Ｏｓｅｅｎ奇异子边界元法与水域有限差分法的组合行之有效。模拟计算解释了水翼处在尾流场中会因参数设置不当产生发散的或等幅的涡激振动，并被试验从定性上核证。