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109/06/09 14:00 成功大學水利及海洋工程學系陳佳琳助理教授 演講
演講公告
張貼人：網站管理員 ╱ 公告日期：2020-06-04演 講 公 告
主講人：陳佳琳 助理教授
地點：中央大學科學一館S-325教室
摘要：
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講題：Dynamics and Variability of Topography-induced Shear Instabilities in Western Boundary Currents
主講人：陳佳琳 助理教授
成功大學水利及海洋工程學系
時間：06月09日（星期二）下午2點
地點：中央大學科學一館S-325教室
摘要：
Shear instability is one of the most important turbulence generation mechanisms in the ocean, in which flow instabilities develop in stratified shear flows and dominate the flow dynamics and mixing. Proper parameterization of small-scale physical processes is required in large-scale ocean models because the horizontal grid resolution (O(km)) in these models is typically much greater than the size of instability waves. The accurate prediction of shear instabilities and the corresponding mixing efficiency can improve model accuracy of the large-scale circulation and transport in the ocean. Therefore, studies on small-scale processes, for example, shear instabilities, provide insight on turbulent mixing processes in the ocean. The properties of shear instabilities, such as the length scales in both horizontal and vertical directions and the frequency, are of key interest in determining the mixing efficiency. A high resolution model with Large Eddy Simulation (LES) closure is applied to investigate the dominant mechanism controlling the scale of shear instabilities in stratified shear flow at high Reynolds Number (Re ~ O(105)). Model experiments indicate the criterion of Froude number (Fr=U/NL) for the characteristic scales of instability waves. The analyses of model experiment and direct measurements of turbulence suggest that the period of instability waves strongly depend on the Froude number and high turbulence is mainly populated in the forward inclined, asymmetric, cusp-like bands.
Keywords: shear instability, mixing, direct measurements of turbulence, LES model
最後修改時間：2020-06-04 AM 9:38
