Wave Transformations over Porous Media
Date Issued
2006
Date
2006
Author(s)
Chang, Yu
DOI
zh-TW
Abstract
ABSTRACT
The purpose of this research is to investigate wave deformation passing through different submerged porous obstacles. The theoretical model is based on the Boussinesq equation demonstrated by Cruz et al. (1997), expressed by depth-averaged velocity and depth-averaged seepage velocity, and it introduces a parameter related with shoaling and seabed contour, Madsen and Sørensen (1991), to apply to the situation a larger relative depth, h/L. The numerical model uses the Fourth-Order Adams-Bashforth-Moulton Predictor-Corrector Scheme and is coupled with source function and absorbing boundary condition to increase the stability of calculation and to decrease the required processing time. The results are quite well in comparison with previous research. After examining the effect upon the porosities and the intrinsic permeability ,kp under different wave conditions, the deformation of the primary wave, second order harmonic wave and third order harmonic wave indicates that the wave height decreases as the relative depth increases when the condition of the porosity is less than 0.44 and kp=2.5×10-8m2. The wave height decreases significantly along with the larger porosity when the relative depth is between 0.293 and 0.489. But the phenomenon of the wave height decrease for the various porosities is not so regular when the relative depth is less than 0.2. The reason of the above situation is the larger non-linear effect at the shallow water condition; therefore the simulation of the wave passing through a porous obstacle is not suitable. When kp=2.5×10-7m2, the wave height does not decrease simply with the increase of the porosity; rather the porosity must be greater than a specific value in order to achieve a greater wave energy decay.
Subjects
布斯尼斯克方程式
透水介質
孔隙率
boussinesq equation
porous media
porosity
Type
thesis
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