花蓮港自防波堤擴建後，颱風波浪常常造成港池共振問題，讓船隻停泊困難，更嚴重則造成船隻因斷纜而發生碰撞。為了解花蓮港受外海波浪引起之共振問題，本研究蒐集花蓮港口之颱風波浪資料，利用FUNWAVE模式進行模擬計算，以JONSWAP波譜為入射波浪條件，分別探討示性波高固定、尖峰週期改變，與週期固定、示性波高改變之情況下，港內15、17及23號碼頭之亞重力波之分布與波譜變化。模式分析結果顯示，示性波高能量在港外均已消散，波高固定改變尖峰週期之情況，亞重力波之分布與其尖峰週期並無規律，但可得到亞重力波之尖峰週期。然而在波高改變週期固定下，港內亞重力波尖峰週期能量會隨示性波高增加而加大。 After the expansion of thebreakwater in HualienHarbor, typhoon waves often cause long-periodoscillations. The oscillations would not only cause berthing difficulties, but alsoresult invessels collisions due to the broken mooring ropes. To investigate the harbor oscillation induced by offshore energetic waves, a numerical model FUNWAVE is used to simulate infragravity waves inside the harbor during the typhoon wave events.Numerical experiments by using a series of incident JONSWAP spectrum are simulated. We discuss the cases of fixed significant wave height with varying peak periods and fixed peak period with varying significant wave heights.Infragravity wave and spectrum at the wharves 15,17, and 23 arestudied. Model results revel the short waveshave dissipatesignificantly outside the harbor. Therelation betweenthe peak period of infragravity waves and fixed significant wave height withvarying periods is unclear. However,for the case of fixed period withvaryingsignificant wave height, the energy of the peak period infragravity waveswouldincrease with the increase of significant wave height.
