Author(s): Ghufran Ahmed Pasha; Norio Tanaka
Linked Author(s): Norio Tanaka
Keywords: No Keywords
Abstract: The effectiveness of coastal vegetation as a barrier to mitigate a tsunami greatly depends on the magnitude of tsunami and vegetation structure. This paper summarizes a series of laboratory experiments that investigated the hydraulic jump formed on upstream vegetation, and the resulting energy loss due to a jump. The characteristics of the jump were determined against vegetation of variable density (G/d, where G=spacing of each cylinder in cross-stream direction, d=diameter of cylinder), and initial Froude number (Fr, where Froude number is obtained from a model without vegetation in the flume). In super-critical flow (Fr =1.67–1.83), a weak hydraulic jump was formed on upstream side of vegetation. The results highlighted the significant effect of denser vegetation as the height of the jump, its location, and the resulting energy loss increased by increasing the vegetation density.