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长细比对光滑圆柱气动力特性影响的试验研究 预览
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作者 黄伯城 马文勇 +2 位作者 柴晓兵 曾建平 杨家 《振动与冲击》 EI CSCD 北大核心 2019年第14期195-201,共7页
工程中存在大量的圆形断面细长结构,其常在强风下发生大幅振动,在细长圆柱的风荷载测试中,由于风洞尺寸的限制,常常采用不同长细比的试验模型进行测试,因此长细比是影响该类结构气动力测试结果的重要试验参数之一。采用刚性模型测压风... 工程中存在大量的圆形断面细长结构,其常在强风下发生大幅振动,在细长圆柱的风荷载测试中,由于风洞尺寸的限制,常常采用不同长细比的试验模型进行测试,因此长细比是影响该类结构气动力测试结果的重要试验参数之一。采用刚性模型测压风洞试验,对亚临界、临界区及超临界区不同长细比圆形断面柱体中心局部气动力及风压分布随长细比的变化规律进行分析。结果表明:对于采用4倍直径端板的有限长度圆柱模型,跨中气动力特性随着长细比的变化规律并不连续,在亚临界区,当长细比小于等于9时,跨中的气动力结果受长细比的影响较大,与二维圆柱试验结果有较大差异;在临界区,跨中的气动力试验结果受长细比的影响相对较小,并呈现较强的三维特性,若圆柱一侧出现稳定的单分离泡区域,其长细比应大于11;进入超临界区后,当长细比小于等于9时,圆柱的流动状态进入单分离泡流域。 展开更多
关键词 光滑圆柱 长细比 气动力特性 临界雷诺数 风洞试验
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Test Research on Influence of Draft on Towing Behaviors of 3-Bucket Foundation Platform* 预览
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作者 乐丛欢 杨家 +1 位作者 丁红岩 张浦阳 《天津大学学报:英文版》 EI CAS 2016年第5期419-425,共7页
To investigate the natural frequencies and towing behaviors of a 3-bucket foundation platform at different drafts, the decay and towing experiments were carried out in a towing tank on a scale of 1:20. The air pressur... To investigate the natural frequencies and towing behaviors of a 3-bucket foundation platform at different drafts, the decay and towing experiments were carried out in a towing tank on a scale of 1:20. The air pressure inside the bucket foundations, the water pressure at the bottom of the bucket foundations, the acceleration of the platform and the towing force were determined in the test process. The time-history curves of the measured parameters were obtained, and the frequency responses of the parameters at different drafts were analyzed by means of fast Fourier transform(FFT). The results showed that the platform natural frequency of heave decreased slightly with the rise of draft. The natural frequencies of roll and pitch are much lower than that of heave, and they increased slightly with the increase of draft. When towing in the following sea, the maximum acceleration of surge, sway and heave has downward trends with the increase of draft, but the change range decreased gradually with the increase of draft. When the draft is 5.0 m(the ratio of draft to bucket height is 0.56), the towing dynamic responses achieve the maximum, which is not conducive to the towing of the platform. When the draft is 6.0 m(the ratio of draft to bucket height is 0.67), the towing dynamic responses are the most stable. 展开更多
关键词 BUCKET foundation platform DRAFT TOWING behavior model test frequency DOMAIN ANALYSIS time DOMAIN ANALYSIS
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