CAJ | 학술논문

研究水下结构的声辐射问题时，流体声介质通常被假设为无限域，然而对于大部分水面海洋结构物，则是部分浸没在水中，自由液面的作用不可忽略。通过构造反对称边界条件来考虑自由液面的影响，采用有限元法结合间接边界元法研究水中部分浸没悬臂平板的振动和声辐射特性。首先，计算悬臂平板在不同浸没深度下的固有频率和模态振型，并与已有文献的算例进行对比分析，验证该方法的正确性；然后，对半浸没悬臂板的声辐射特性进行计算，并讨论载荷位置和浸没深度对平板声振特性的影响。研究表明：平板在水中的固有频率随着浸没深度的增加而降低；载荷位置对平板辐射声功率级有影响且和频率有关；平板辐射声功率是随着浸没深度的增加而增大，低频段辐射声功率曲线的峰值随着深度的增大有向低频移动的趋势。
연구수하결구적성복사문제시，류체성개질통상피가설위무한역，연이대우대부분수면해양결구물，칙시부분침몰재수중，자유액면적작용불가홀략。통과구조반대칭변계조건래고필자유액면적영향，채용유한원법결합간접변계원법연구수중부분침몰현비평판적진동화성복사특성。수선，계산현비평판재불동침몰심도하적고유빈솔화모태진형，병여이유문헌적산례진행대비분석，험증해방법적정학성；연후，대반침몰현비판적성복사특성진행계산，병토론재하위치화침몰심도대평판성진특성적영향。연구표명：평판재수중적고유빈솔수착침몰심도적증가이강저；재하위치대평판복사성공솔급유영향차화빈솔유관；평판복사성공솔시수착침몰심도적증가이증대，저빈단복사성공솔곡선적봉치수착심도적증대유향저빈이동적추세。
While studying the underwater acoustic radiation problem, the fluid is usually assumed to be in?finite;yet, most marine structures are only partially submerged in water, suggesting that the free surface ef?fect should not be ignored. In this paper, the free surface effect is simulated with an anti-symmetric plane set. The vibration and sound radiation characteristics of partially submerged cantilever plates are analyzed by employing the finite element method combined with the indirect boundary element method. The natural frequencies and mode shapes of the cantilever plate at different immersion depths are first obtained and compared with the actual data, which validates the proposed method. Then, the half-immersed plate's vi?bro-acoustic characteristics are calculated, on which the impact of different load positions and immersion depths is discussed as well. It is observed that the natural frequency of the immersed plate decreases with the increase of the immersion depth. Also, the load position would influence the sound power level of the plate, and the exact influence is related to the frequency. Plus, the plate's sound power level increases with the increase of the immersion depth, and the peak of acoustic radiation power curve tend to move toward low frequency range as the immersion depth rises.