A variational solution of 2-D sound-structure interaction problems

Based on the fluid-structure coupling theory, a localized variational principle for analyzing the sound radiation from elastic structure submerged in water due to harmonic excitations is presented. It will be a powerful tool to formulate various numerical methods for steady response of structural-acoustic systems. By means of this variational principle a hybrid element method, in which an analytical solution valid in most of the surrounding water is incorporated with finite elements distributed in the structure and its neighboring water, is devised. Computational examples are then given to demonstrate its high accuracy and time saving.

流固耦合谐振分析的局部变分原理及其杂交元算式

针对埋入二维无限域流场中一般结构的谐耦振问题,提出了相应的局部变分原理,并用圆形人工边界将无限域分成两部分,在人工边界内的结构及流场采用有限元数值解,人工边界外无穷大域则采用满足Sommerfeld辐射条件的解析解。通过构造泛函,使得提出的变分方程和给定谐耦振的边值问题完全等价。在此基础上进一步建立了杂交元算式,它能保证在圆形人工边界上数值解和解析解两种场函数及其导数的相容性。算例检验表明本文方法结果正确,而且具有很高的计算效率。通过基于大型软件的二次开发,将新的理论方法融入到常规的流固耦合分析中,极大地简化了编程和计算,为类似的理论研究提供了简便的数值计算实现途径。