{"title":"S 形崖状弹性片的流动诱导振动","authors":"Junkyu Ham, Minho Song, Janggon Yoo, Daegyoum Kim","doi":"10.1016/j.jfluidstructs.2024.104120","DOIUrl":null,"url":null,"abstract":"<div><p>The dynamics of an S-shaped elastic sheet, in which the inclination angles of two clamped ends are normal to the direction of uniform flow and opposite to each other, are experimentally investigated. Flow-induced vibrations are ensured in this novel configuration by the substantial area perpendicular to the flow and the bluff shape. The motions of the sheet can be divided into three modes depending on the trends of the oscillation amplitude and frequency with respect to the flow velocity. At low flow velocities, the sheet undergoes small-amplitude oscillations with a nearly constant frequency. Beyond a certain threshold of flow velocity, the amplitude increases rapidly while the frequency declines. The dimensionless critical flow velocity is almost independent of the ratio between the clamp distance and sheet length, as predicted by simple scaling analysis. As the flow velocity increases further, the amplitude becomes saturated, while the frequency becomes almost proportional to the flow velocity. The most notable features of the sheet are the temporal and spatial distributions of its bending energy. The bending energy exhibits negligible fluctuations over time, and despite changes in the flow velocity, the time-averaged bending energy remains almost constant. However, by dividing the sheet into front, center, and rear parts, significant variations in the bending energy are found, and these are intensified at higher flow velocities. The S-shaped sheet exhibits more pronounced variations in local bending energy at lower flow velocities compared with a snap-through sheet model clamped at both ends.</p></div>","PeriodicalId":54834,"journal":{"name":"Journal of Fluids and Structures","volume":"127 ","pages":"Article 104120"},"PeriodicalIF":3.4000,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Flow-induced vibration of an S-shaped bluff elastic sheet\",\"authors\":\"Junkyu Ham, Minho Song, Janggon Yoo, Daegyoum Kim\",\"doi\":\"10.1016/j.jfluidstructs.2024.104120\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The dynamics of an S-shaped elastic sheet, in which the inclination angles of two clamped ends are normal to the direction of uniform flow and opposite to each other, are experimentally investigated. Flow-induced vibrations are ensured in this novel configuration by the substantial area perpendicular to the flow and the bluff shape. The motions of the sheet can be divided into three modes depending on the trends of the oscillation amplitude and frequency with respect to the flow velocity. At low flow velocities, the sheet undergoes small-amplitude oscillations with a nearly constant frequency. Beyond a certain threshold of flow velocity, the amplitude increases rapidly while the frequency declines. The dimensionless critical flow velocity is almost independent of the ratio between the clamp distance and sheet length, as predicted by simple scaling analysis. As the flow velocity increases further, the amplitude becomes saturated, while the frequency becomes almost proportional to the flow velocity. The most notable features of the sheet are the temporal and spatial distributions of its bending energy. The bending energy exhibits negligible fluctuations over time, and despite changes in the flow velocity, the time-averaged bending energy remains almost constant. However, by dividing the sheet into front, center, and rear parts, significant variations in the bending energy are found, and these are intensified at higher flow velocities. The S-shaped sheet exhibits more pronounced variations in local bending energy at lower flow velocities compared with a snap-through sheet model clamped at both ends.</p></div>\",\"PeriodicalId\":54834,\"journal\":{\"name\":\"Journal of Fluids and Structures\",\"volume\":\"127 \",\"pages\":\"Article 104120\"},\"PeriodicalIF\":3.4000,\"publicationDate\":\"2024-04-15\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Fluids and Structures\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0889974624000550\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, MECHANICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Fluids and Structures","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0889974624000550","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 0
摘要
实验研究了 S 形弹性片的动力学,其中两个夹持端面的倾斜角与均匀流动方向的法线方向相反。在这种新颖的构造中,垂直于流动的大面积区域和崖壁形状确保了流动引起的振动。根据振幅和频率随流速变化的趋势,薄片的运动可分为三种模式。在低流速条件下,薄片以几乎恒定的频率进行小振幅振荡。当流速超过某一临界值时,振幅迅速增大,而频率则逐渐减小。正如简单的比例分析所预测的那样,无量纲临界流速几乎与夹持距离和薄片长度之间的比率无关。随着流速的进一步增加,振幅趋于饱和,而频率则几乎与流速成正比。薄片最显著的特征是其弯曲能的时间和空间分布。弯曲能随时间的波动可以忽略不计,尽管流速发生了变化,但时间平均弯曲能几乎保持不变。然而,如果将薄片分为前部、中部和后部,就会发现弯曲能有明显的变化,而且在流速较高时,这种变化会加剧。与两端夹紧的卡入式薄片模型相比,S 形薄片在较低流速下的局部弯曲能变化更为明显。
Flow-induced vibration of an S-shaped bluff elastic sheet
The dynamics of an S-shaped elastic sheet, in which the inclination angles of two clamped ends are normal to the direction of uniform flow and opposite to each other, are experimentally investigated. Flow-induced vibrations are ensured in this novel configuration by the substantial area perpendicular to the flow and the bluff shape. The motions of the sheet can be divided into three modes depending on the trends of the oscillation amplitude and frequency with respect to the flow velocity. At low flow velocities, the sheet undergoes small-amplitude oscillations with a nearly constant frequency. Beyond a certain threshold of flow velocity, the amplitude increases rapidly while the frequency declines. The dimensionless critical flow velocity is almost independent of the ratio between the clamp distance and sheet length, as predicted by simple scaling analysis. As the flow velocity increases further, the amplitude becomes saturated, while the frequency becomes almost proportional to the flow velocity. The most notable features of the sheet are the temporal and spatial distributions of its bending energy. The bending energy exhibits negligible fluctuations over time, and despite changes in the flow velocity, the time-averaged bending energy remains almost constant. However, by dividing the sheet into front, center, and rear parts, significant variations in the bending energy are found, and these are intensified at higher flow velocities. The S-shaped sheet exhibits more pronounced variations in local bending energy at lower flow velocities compared with a snap-through sheet model clamped at both ends.
期刊介绍:
The Journal of Fluids and Structures serves as a focal point and a forum for the exchange of ideas, for the many kinds of specialists and practitioners concerned with fluid–structure interactions and the dynamics of systems related thereto, in any field. One of its aims is to foster the cross–fertilization of ideas, methods and techniques in the various disciplines involved.
The journal publishes papers that present original and significant contributions on all aspects of the mechanical interactions between fluids and solids, regardless of scale.