In order to investigate the effects on the underwater radiated noise of a stiffened cylindrical shell due to welded defect, a stiffened cylindrical shell with welded defects was studied via finite element method coupled with boundary element method. The underwater radiated noise of the structure with different lengths, angles, positions of defect and numbers of rib containing defects was calculated, and the frequency response function of radiated noise was obtained. The comparison and analysis of the results show that the lengths, angles, position of defects and number of ribs containing defects have effects on underwater radiated noise. Generally, the effects of defected rib nearer the bulkhead on the radiated noise are less. According to different lengths, angles, position of defects and number of defected ribs, a comprehensive analysis on the structural radiated noise can be carried out in the engineering application. The results can be used to analyze the radiated noise measurement of submarine.%基于CFD软件对滑行艇二维简化模型在均匀来流中的运动响应进行数值分析.根据滑行艇的流体动力数值计算结果实时求解滑行艇的运动响应特性,对4种不同傅汝德数下滑行艇的纵摇与垂荡耦合运动特性进行研究,得到艇体升沉幅值、纵摇角随时间的变化特性,以及阻力、升力和力矩随傅汝德数的变化规律,并分析了艇体达到稳定状态所需时间和滑行过程中艇底动压力的变化特性.研究表明:傅汝德数1.5时达到稳定滑行状态的时间仅为80 s;除了在傅汝德数2.0时发生严重振荡,其余3种情况下滑行艇均能够趋于一种“动平衡”状态.
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