臺大理論科學研究中心於10月22日(星期二) 上午，邀請新加坡大學講座教授 劉立方院士來校演講，歡迎參加!

講題 : On the three-dimensional transition in the boundary layer beneath a solitary wave

時間 : 2019年10月22日(星期二) 9:10 - 11:00
地點 : 國立臺灣大學 工程科學與海洋工程學系 二樓視聽室

摘要 : 

The transient boundary layer developing under a solitary wave is analyzed for two essential steps of bypass transition, the streak growth and breakdown. To initiate the process, a linearly optimal cross-stream forcing is employed, which is found using an input-output framework, based on an adjoint method. Optimal forcing configurations are deployed to nonlinear equations, and streaks of various amplitude are generated via lift- up mechanism. The secondary stability of streaks is examined and the most unstable modes are found to be sinuous modes. Streamwise vortices with intensities in the range of 0.5% of maximum wave orbital velocity are sufficient to develop unstable streaks. In the final step, the nonlinear development and breakdown of unstable streaks are investigated using direct numerical simulations, and further estimates for transition to turbulence are provided. 

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National Taiwan University
Center for Advanced Study in Theoretical Sciences
國立臺灣大學 理論科學研究中心
專任研究助理 劉至芳
E-Mail：tassist2@tims.ntu.edu.tw
TEL：( 886)02-3366-9901