基于谱单元方法的平板冲击流固耦合研究

假设流体无粘且无旋，计及流体中的气穴现象，采用谱单元方法建立水下爆炸瞬态流固耦合的三维数值模型，探讨了水下爆炸瞬态流固耦合作用的机理，用经典的平板冲击问题对数值模型进行验证，数值结果与解析解吻合良好，并根据数值结果绘制了流体中的气穴区域，对气穴效应进行分析，分析显示，气穴效应会对结构响应产生很大影响，在计算中应予以考虑。基于本文建立的数值模型，在不同网格细化的条件下，分别采用谱单元方法和有限元方法对弹簧——平板模型进行水下爆炸瞬态流固耦合问题的求解，并在此基础上对谱单元方法和有限元方法进行对比研究，研究发现，谱单元方法在提高精度的同时能大量节省计算时间，可较好地应用于水下爆炸流固耦合问题的求解中。本文旨在为相关水下爆炸瞬态流固耦合的研究提供参考。

Transient fluid-structure interaction with spectral element method

Spectral element method was used here to establish a numerical model for calculating the transient fluid-structure interaction in underwater explosion.The fluid was assumed to be inviscid and irrotational,with cavitation phenomenon considered.The numerical model was validated with a classical flat plate in underwater shock problem and the numerical results coincided well with the analytic solution.The cavitation region was also plotted and analyzed and the results showed that the cavitation effect is necessary to be considered in numerical simulation since it can influence the structural response severely.Based on the numerical model built here,the interaction between a spring-plate and fluid in underwater explosion was calculated with the spectral element method(SEM) and the finite element method(FEM),respectively with various mesh refinements.Through comparison between SEM and FEM,it was shown that SEM can save a lot of computing time and raise the precision as well.The study results provided a reference for fluid-structure interaction research in underwater explosion.