Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8063293 | Ocean Engineering | 2018 | 11 Pages |
Abstract
The Great East Japan tsunami revealed the limits of using only a sea embankment for defense. Therefore, a compound defense system combining a coastal forest and sea embankment for a tsunami overflowing the embankment is proposed to mitigate damage. This study was conducted to clarify the changes in overflow volume from an embankment due to the location and thickness of a coastal forest. The effect of tree overturning was also investigated in relation to changes in wave height. A flume with a gate quickly lifted by air pressure to create an unsteady tsunami-like bore was used to investigate the changes in overflow volume and the reflection characteristics of various compound-defense models. The results show that a landward forest has the advantage of decreasing the fluid force behind the forest, and seaward forest can reduce overflow volume landward. Even when the sea-side forest is thin, the change in flow pattern in front of the embankment increases its total reflection and decreases the overflow volume by approximately 10%, although the forest itself does not increase the reflection. A thin seaward and overturned forest also decreases the overflow volume when the approaching tsunami height was less than the embankment height.
Keywords
Related Topics
Physical Sciences and Engineering
Engineering
Ocean Engineering
Authors
Yoshiya Igarashi, Norio Tanaka,