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107/01/17 10:00 新加坡國立大學劉立方教授 演講

演講公告
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演 講 公 告
 

講題：Boundary layer flows induced by a solitary wave
 

主講人：劉立方　教授
 
　　　　新加坡國立大學
 
時間：01月17日（星期三）上午10點
 

地點：中央大學科學一館S-325教室
 

摘要：
 
　　In this presentation I will discuss the bottom boundary layer flows under a solitary wave propagating over a constant depth or running up a uniform slope.
　　First, approximate analytical solutions for a laminar bottom boundary layer flow will be discussed for the case of constant depth (Liu and Orfila 2004). The flow reversal occurs near the bottom during the deceleration phase for relatively small Reynolds numbers. Laboratory experiments were performed to check the analytical results (Liu, Park and Cowen 2007). Laboratory experiments also demonstrated that for larger Reynolds numbers, vortex tubes were triggered near the bottom (Sumer et al. 2010). The results of linear instability analysis will be discussed (Sadek et al. 2015). For even larger Reynolds numbers boundary layer flows eventually become turbulence.
　　I will also discuss some of the new (experimental and numerical) findings for swash flows generated by a non-breaking solitary wave on a constant slope (Higuera et al. 2017). The feature of boundary layer flow reversal also occurs during the uprush phase. However, during the down rush phase a hydraulic jump occurs and a series of vortices are generated from the boundary layer in the vicinity of the jump. The effects of contact angle and meniscus in the vicinity of moving shoreline will also be briefly discussed (Park, Liu and Chan 2012).
 

The following references might be useful for reader:
  1. Liu, P. L.-F. and Orfila, A. (2004) Viscous effects on transient long wave propagation. J. Fluid Mech., 520: 83-92. http://dx.doi.org/10.1017/S0022112004001806
  2. Liu, P. L-F. Park, Y.S. and Cowen, E. A. (2007) Boundary layer flow and bed shear stress under a solitary wave. J. Fluid Mech., 574: 449-463. http://dx.doi.org/10.1017/S0022112006004253
  3. Sumer, B. M., Jensen, P. M., Sorensen, L. B., Fredsoe. J., Liu, P. L.-F., Carstensen, S. (2010) Coherent structures in wave boundary layers. Part 2. Solitary motion. J. Fluid Mech., 646, 207-231. http://dx.doi.org/10.1017/S0022112009992837
  4. Sadek, M. M., Parras, L., Diamessis, P.J., and Liu, P. L.-F. (2015) Two-dimensional instability of the bottom boundary layer under a solitary wave. Phys. Fluids, 27, 044101(2015). http://dx.doi.org/10.1063/1.4916560
  5. Park, Y.S., Liu, P. L-F. and Chan, I-C. (2012) Contact line dynamics and boundary layer flow during reflection of a solitary wave. J. Fluid Mech., 707: 307-330. http://dx.doi.org/10.1017/jfm.2012.280
  6. Higuera, P., Liu, P. L-F., Lin, C., Wong, W-Y., Kao, M-J. (2017) Laboratory-scale swash flows generated by a non-breaking solitary wave on a steep slope. (in revision).
 
最後修改時間：2018-01-12 AM 11:32

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