| An experimental investigation of the velocity field under cnoidal waves over the asymmetric rippled bed |
| |
| 作者姓名： | CHENG Yongzhou WANG Yongxue JIANG Changbo CHEN Chun |
| |
| 作者单位： | CHENG Yongzhou1，2*，WANG Yongxue1，JIANG Changbo2，CHEN Chun21. State Key Laboratory of Coastal and Offshore Engineering，Dalian University of Technology，Dalian 116024，China2. Department of River and Ocean Engineering，Changsha University of Science and Technology，Changsha 410076，China |
| |
| 摘 要： | 1 IntroductionIn coastal areas a ubiquitous phenomenon is theformation of ripples in the seabed. It is now widelyaccepted that the flow and sediment transport overseabed are vital in relation to erosion, surface wavedissipation and pollution dispersion et…
|
| 关 键 词： | 不对称波动海床 椭圆余弦波 速度场 实验研究 |
| 收稿时间： | 2006-05-20 |
| 修稿时间： | 2006-10-25 |
An experimental investigation of the velocity field under cnoidal waves over the asymmetric rippled bed |
| |
| CHENG Yongzhou,WANG Yongxue,JIANG Changbo,CHEN Chun.An experimental investigation of the velocity field under cnoidal waves over the asymmetric rippled bed[J].Acta Oceanologica Sinica,2007,26(1):130-139. |
| |
| Authors: | CHENG Yongzhou WANG Yongxue JIANG Changbo and CHEN Chun |
| |
| Institution: | 1.State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China;Department of River and Ocean Engineering, Changsha University of Science and Technology, Changsha 410076, China2.State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China3.Department of River and Ocean Engineering, Changsha University of Science and Technology, Changsha 410076, China |
| |
| Abstract: | The evolution of an initially flat sandy bed is studied in a laboratory wave flume under cnoidal waves and acoustic Doppler velocimeter (ADV) was utilized in the detailed velocity measurements at different positions. The ripple formation and evolution have been analyzed by CCD images and the asymmetric rippled bed is induced by the nonlinear wave flow. The flow structure and a complete process of vortex formation, evolvement and disappearance were observed on the asymmetric rippled bed under cnoidal waves. With the increasing nonlinearity of waves, which is an important factor in the sand ripple formation, the vortex intensity becomes stronger and shows different characteristics on both sides of the ripple crest. The vorticity and wave velocity reach their maximum values at different phase angles. The vortex value reaches the maximum value at a small phase angle with the increasing Ursell number. The near bed flow patterns are mainly determined by the ripple forms and the averaged longitudinal velocity over a wave period above the ripple trough and crest are positive, which indicates the possibility of significant onshore sediment transport and a corresponding ripple drift. The phase averaged vertical velocity has noticeable positive values near the bottom of the ripple crest and trough. Sediments may be lifted from the ripple surface, picked up in suspension by the local velocity, and deposited over the crest and on the lee of the ripples. |
| |
| Keywords: | ripple cnoidal wave velocity vortex |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《海洋学报(英文版)》浏览原始摘要信息 |
| 点击此处可从《海洋学报(英文版)》下载免费的PDF全文 |
