Present time-dependent wave transformation models such as Bussinesq-type models can simulate standing waves in front of a vertical wall using a perfect reflection boundary. The waves in front of actual seawalls and harbor breakwaters, however, are rather partial standing waves such that some incident wave energy is dissipated, especially when covered with wave energy dissipating blocks.
　Recently we reported on a new boundary model developed to reproduce the partial standing waves in a Boussinesq-type wave transformation model, named a porous boundary. This model consists of a special porous region where wave energy is dissipated due to laminar and turbulent flow resistances, and can reproduce the amplitude and phase of partial standing waves.
　In the present report, numerical calculations are systematically carried out to conduct a basic parameter study on wave conditions and porous media, i.e., concrete blocks and geotextile wave-absorber. Another series of numerical calculations are also conducted to investigate the suitability of using the wave transformation model with this porous boundary model. Resultant wave profiles in front of the boundary, wave spectrum, and reflection coefficient are compared with values obtained from model experiments in a wave flume. Major conclusions are as follows:
1)The reflection coefficient of the porous boundary varies significantly with porosity, i.e., when porosity is from 0.3 to 0.8, the reflection coefficient is small; becoming smaller with decreasing wave period and increasing wave height as predicted.
2)Wave energy dissipation mainly occurs by turbulent flow resistance for a geotextile wave-absorber having large porosity and small diameter.
3)Partial standing waves in front of a vertical wall covered with concrete blocks are suitably reproduced by the model.
4)Simulations agree well with experimental results using geotextile wave-absorber in that it can effectively reduce the reflection coefficient.
5)Calculations and experiments for a solid vertical wall indicate that calculational reflection coefficients are about 1.0, while experimental ones are relatively low ranging from 0.6-1.0. Experimental results may include the effect of wave damping due to friction of the walls and/or measurement errors, which should both be investigated further.