Search

A field survey of Fukuura Coast (in Tokyo Bay, Japan) revealed during the passage of Typhoon Faxai in 2019 waves with considerable momentum caused significant wave overtopping, resulting in structural damage to coastal defenses and localized flooding. The hindcasted wave height using a third-generation wave model was not high enough to explain the extent of the local damage at Fukuura Coast, likely due to such methods failing to take into account the strong gust-winds recorded during the passage of the typhoon. To solve such problems the authors developed a new numerical model that takes into account the dynamic interaction of air and water, based on the finite volume method (FVM) and the volume of fluid method (VOF). Although this model still slightly underestimates the measurements in the experiments previously conducted by different authors, it is better than existing methods when estimating the overtopping rates under strong winds. The model was then applied to a real-scale model of Fukuura Coast, where by taking into account strong gust-wind speed of 41 m/s the authors were able to explain the phenomena that took place. [ABSTRACT FROM AUTHOR]

Quantitative assessments on the effect of translate speed of typhoons on wind waves were carried out. A WRF-SWAN coupled model that used observed meteorological data was applied to eight different typhoons in the vicinity of Shiono-Misaki, on the pacific side of Honshu Island, Japan. The authors proposed a new methodology to modify the translate speed and wind field of tropical cyclones using an empirical model in which the gross wind speed is expressed as the summation of two different types of wind generation. Two different trends of the relationship between the significant wave height ( H s ) and translate speed (V ) were found, describing the most dominant parameter. Typhoons with a modest intensity and size (for the case of Japan) generally showed a positive correlation between the change in the maximum H s and V , which means translation wind speed was the dominant parameter. In contrast, stronger typhoons were less sensitive to the change in V and could maintain high waves even when almost stationary. With reference to the results, it is important to raise awareness of the future problems that could be caused by large storms that stall for prolonged periods of time. [ABSTRACT FROM AUTHOR]