摘要
基于线性势流理论,应用特征函数展开方法和透空壁内流体速度与两壁间压力差成正比的线性模型,建立了上部带有透空结构的截断圆筒绕射问题和辐射问题的解析模型,进而导出浮体的垂荡运动响应幅值算子计算公式。通过与直立透空圆筒和非透空截断圆柱的相关结果进行对比,验证了该文推导的正确性。通过数值计算研究了透空系数、圆筒内外径比(内圆柱半径和圆筒半径之比)和吃水比(透空结构吃水和圆筒吃水之比)对整个圆筒的垂向水动力特性(运动响应幅值、附加质量、辐射阻尼和波浪激振力)的影响,并与非透空截断圆柱的计算结果进行对比分析。结果表明随着透空系数的增大,结构的附加质量和辐射阻尼呈增加趋势,垂荡运动响应幅值算子的峰值呈明显减小趋势,并且在低频区垂向波浪激振力相对较小,这有利于增加浮式结构的稳定性;内外径比和吃水比均对透空结构的垂向水动力特性影响较大。
Based on the linear potential flow theory, an analytical model for the diffraction and radiation problem of a trtmcated cylinder with upper porous wall and inner columns has been built by using the eigenfunction expansion method and the linear relationship between the pressure difference on the two sides of the porous wall and the fluid velocity inside it. Then, the formulae for the heave RAO （Response Amplitude Operator） was deduced. The model was verified by comparing the present results with the published results for the vertical porous cylinder and that for the impermeable truncated cylinder. The effect of porous coefficient, the radius ratio （ratio of the radius of the inner column to that of the outer cylinder）, and the draft ratio （ratio of the draft of the inner column to that of the outer cylinder） on the vertical hydrodynamics （response amplitude, added mass, radiation damping and the exciting force） of the cylinder in a heave mode were investigated. The analytical results showed that： the added mass and the radiation damping increase with the increasing of the porous coefficient, and the opposite is true for peak value of heave RAO, also the considerable reduction of a vertical exciting force was found in the lower frequency region, those may improve the stability of the structure; the radius ratio and the draft ratio affect the vertical hydrodynamics of the cylinder significantly.
出处
《工程力学》
EI
CSCD
北大核心
2017年第12期239-247,共9页
Engineering Mechanics
基金
国家自然科学基金项目(51379037
51679036)
教育部新世纪优秀人才计划项目(NCET-13-0076)
关键词
透空结构
漂浮圆筒
势流
垂荡
水动力特性
porous structure
floating cylinder
potential flow
heave motion
hydrodynamic characteristics
