Boundary layer flow and bed shear stress under a solitary wave
Boundary layer flow and bed shear stress under a solitary wave
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DOI：
10.1017/s0022112006004253
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发表时间：
2007-02
影响因子：
3.7
通讯作者：
P. Liu;Y. Park;E. Cowen
中科院分区：
文献类型：
--
作者：
P. Liu;Y. Park;E. Cowen
Liu和Orfila（J.FluidMech.vol.520，2004，p.83）推导了瞬态长波下粘性边界层流动的解析解。在动量方程中忽略非线性惯性力的假设下，得到了它们的解析解。本文利用Liu & Orfila的解和非线性边界层方程的解，研究了孤立波作用下的边界层流动特性。据发现，而边界层外的自由流速度的水平分量总是在波传播的方向上移动，在边界层内的底部附近的流体粒子速度反转方向的波减速。因此，河床剪切应力在减速阶段也改变符号。实验室测量，包括自由表面位移，粒子图像测速（PIV）解决粘性边界层的速度场，并计算床面剪应力也收集到检查的理论结果。观察到极好的一致性。
Liu & Orfila (J. Fluid Mech. vol. 520, 2004, p. 83) derived analytical solutions for viscous boundary layer flows under transient long waves. Their analytical solutions were obtained with the assumption that the nonlinear inertia force was negligible in the momentum equations. In this paper, using Liu & Orfila's solution and the solutions for the nonlinear boundary layer equations, we examine the boundary layer flow characteristics under a solitary wave. It is found that while the horizontal component of the free-stream velocity outside the boundary layer always moves in the direction of wave propagation, the fluid particle velocity near the bottom inside the boundary layer reverses direction as the wave decelerates. Consequently, the bed shear stress also changes sign during the deceleration phase. Laboratory measurements, including the free-surface displacement, particle image velocimetry (PIV) resolved velocity fields of the viscous boundary layer, and the calculated bed shear stress were also collected to check the theoretical results. Excellent agreement is observed.