Study of irregular wave Overtopping rate, Reflection Coefficient and Pressure of Breakwaters

• Main Authors: Kun-Hung Li, 李崑弘
• Other Authors: Jen-Shin Hwang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/s6sz6b

碩士 === 國立成功大學 === 水利及海洋工程學系碩博士班 === 92 === ABSTRACT 　　The purpose of this study was to investigate the effect of irregular wave overtopping on pressure and overtopping rate of breakwaters and reflection coefficient. We adopted the model which Goda considered the wave height probability , and he used the expected wave overtopping rate to present the wave overtopping rate on irregular wave, and calculated the regular wave overtopping from the Hwang ＆ Chang’s (2001) model. About the distribution of wave height , we adopted the cut-off Rayleigh distribution that Goda presented in 1975. In irregular wave pressure, we copied the Hwang ＆Chang’s (2001) model to modify the Sainflou and Goda’s regular wave pressure formula, and used the clapotis wave amplitude to replace the Sainflou and Goda’s clapotis wave amplitude . We also carried out the irregular wave overtopping experiments of breakwaters with different rubble-mound heights. Then we compared the experimental results with the calculated results to discuss the relationship between the crown height and the rubble-mound height of breakwaters and overtopping rate, reflection coefficient and wave pressure. 　　The results showed that the calculated results of overtopping rate and reflection coefficient and the wave crest height in wave overtopping of the present model are conformable to the experimental results. The overtopping rate would increase when the rubble-mound height increased or the crest height decreased but the reflection coefficient would just be counter. The wave pressure in the surface would decrease when the rubble-mound height increase but the wave pressure force was counter. It showed that it’s not obvious to the pressure force when the irregular wave occurred to overtop .The modified Goda’s to calculate the wave pressure force formula was better than Goda’s formula. Finally we presented the experimental formula that people could use more efficiently.