2024 Volume 80 Issue 16 Article ID: 23-16081
The evaluation of the hydrodynamic forces generated by a permeable resistance is important for the proper prediction of tsunamis run up, since they have significant effect on the resistance and attenuation of breaking bores with different Froude numbers (Fr). In this study, basic experiments were conducted to measure temporal variations of wave heights of the breaking bores through a group of cylinders with the different Fr, and results were compared with one-dimensional calculation results based on a theoretically derived hydrodynamic force evaluation method. The larger Fr is, the larger the attenuation of the wave heights and propagation speed of the breaking bores by the permeable resistance. This is considered to be due to a difference in reflection of the breaking bores caused by presence of the resistance. The hydrodynamic force evaluation method used in this study was able to reproduce the longitudinal distribution of the wave height attenuation regardless of the Fr, indicating that conventional evaluation method for uniformly distributed drag coefficients cannot be used to evaluate the attenuation of the wave height and propagation speed regardless of the Fr.
