| Project/Area Number |
17560460
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | Tottori University |
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Principal Investigator |
MATSUMI Yoshiharu Tottori University, Social Systems Engineering, Professor (00135667)
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| Co-Investigator(Kenkyū-buntansha) |
KIMURA Akira Tottori University, Social Systems Engineering, Professor (20027262)
OHNO Kenichi Tottori Univeraty, Information Media Center, Lecturer (90314608)
OHTA Takao Tottori University, Social Systems Engineering, Research Associate (70233129)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,680,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥180,000)
Fiscal Year 2007: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Coastal Structures / Damage of Armour Laver / Performance design / Rubble Mound Breakwater / Multidirectional Waves / Overtopping Rate / Wave Absorption Performance |
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| Research Abstract |
1. Laboratory experiments were conducted in a wave flume to investigate the relation between the performance and damage progression of a rubble mound breakwater. The reflection coefficient, runup height and volume of overtopped water were taken as performance indexes of the breakwater.
2. A time-averaged numerical wave model and semi-empirical overtopping model are applied to computation of wave energy dissipation, reflection coefficient and overtopping rate. The computed reflection coefficient and overtopping rate agree with the measured values. The numerical model predicts the cross-shore variations of the mean and standard deviation of the measured free surface elevation and horizontal velocity reasonably well. The model also predicts the overtopping rate within about a factor of two; however, the reflection coefficient and significant runup height are underestimated for the steep slope of 2/3.
3. The change of reflection coefficient with artificially changing the cross section of bre
… More
akwater is examined from the numerical experiments using CADMAS-SURF. The following were confirmed; the case in which the vanishing wave performance is reduced with the increase in the damage of the armour layer and case in which it does not change.
4. The total wave overtopping rate per unit length of the seawall in 2D waves with the normal direction becomes lager than in 3D waves. The performance of the wave overtopping in 2D wave is sensitively influenced by direction of the incident wave. By investigating the spatial distribution of the local overtopping rate along the seawall model, it can be found that there are positions in which values of the local overtopping rate in the oblique 3D waves are almost equivalent to those in the oblique 2D waves. The simulation model can estimate the characteristic of the spatial change of the local overtopping rate measured in the experiments relatively well.
5. The theoretical model for free low frequency waves which are generated due to the discontinuity between the bound waves systems at the step edge is extend to model for the slope approximated by the finite steps. The comparison of the model and the measurements shows good agreement. Less
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