Numerical modeling of storm surge

• Main Authors: Chi-Yao Lin, 林齊堯
• Other Authors: 蔡丁貴
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/89301464796335573078

碩士 === 國立臺灣大學 === 土木工程學研究所 === 93 === Storm surge is a meteorological tide with abnormal rise of sea level, and is mainly induced by effects of tropical low pressure, especially typhoons in the case of Taiwan. It causes many life casualties and property loses. On the typhoon path, coastal water level rises compared with astronomical tide. It is important to forecast storm surge at river mouth section and coastal areas. This research is to develop a numerical model by employing a boundary-fitted coordinate system. It transforms an irregular plane into a rectangular computational plane. Finite difference method with a predictor-corrector scheme is applied to continuity and momentum equations in the rectangular domain. Sea level departure from mean sea level is then calculated. Traditionally, storm surge model had assumed that wind structure is cylindrically symmetrical in typhoon model. In this study, field wind velocity measurements are used to calculate the surge during typhoons. Numerical results of storm surges by using cylindrically wind structure and field wind velocities are compared. Very closed comparisons are found. In order to demonstrate present model of storm surges, some recorded typhoons are used as examples. Calculated storm surges in coastal regions at Taimsui, Keelung, Hwalien and Kaohsiung are compared with field measurements. Present model shows reasonable forecast capability.