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You are here : eLibrary : IAHR World Congress Proceedings : 35th IAHR Congress - Chengdu (2013) : THEME 6 - MARITIME HYDRAULICS AND COASTAL ENGINEERING : Interaction of Water Waves and a Submerged Parabolic Obstacle in the Presence of a Uniform\Shear Cur...
Interaction of Water Waves and a Submerged Parabolic Obstacle in the Presence of a Uniform\Shear Current Using RANS Model
Author : Yen-Lung Chen, Shih-Lun Hsu and Shih-Chun Hsiao
This paper aims to simulate the regular wave propagating over a submerged parabolic obstacle in the presence of uniform\shear current using the two-dimensional numerical model named COBRAS (COrnell BReaking And Structure). The present numerical model solves the Reynolds-Averaged Navier-Stokes (RANS) equations combined with k-? turbulence closure model, and the free surface deformation is tracked by using volume of fluid method (VOF). To generate wave in the presence of current, the second-order nonlinear analytical solution of Tsao (1959) is applied on the upstream boundary and a ramp function is used to avoid the unwanted fluctuation and reflection. Moreover, the radiation boundary condition is used with varying outflow phase velocity. The capability of numerical model simulating regular wave with weak\moderate current over constant water depth is first validated with available analytical solutions and experimental data. In particular, the particle trajectory in regular wave with uniform current is compared with third-order trajectory solution and laboratory experiment of Chen et al. (2012). Further, the spatial surface elevation and velocity profile at various phases are compared with second-order nonlinear analytical solution of Tsao (1959). Comparisons among the experimental data, analytical solution and present numerical results show good agreements. Then, the regular wave propagating over a submerged parabolic obstacle in the weak\moderate uniform and shear current is investigated. The geometric dimension of simulation is referred to the physical experiment of Zaman and Togashi (1996). Detailed discussions including velocity and vorticity field and relation of free surface and vorticity are given. Interestingly, it is found that the free surface elevation decreases with the increase of the strength of vorticity in both of moderate uniform and moderate shear current with regular wave over a submerged parabolic obstacle.
File Size : 1,795,066 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 35th IAHR Congress - Chengdu (2013)
Article : THEME 6 - MARITIME HYDRAULICS AND COASTAL ENGINEERING
Date Published : 19/07/2016
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