大型浅水湖泊太湖波浪特征及其对风场的敏感性分析

Wave characteristics and sensitivity analysis of the wind field in a large shallow lake-Lake Taihu

以空间均匀的实际风场为驱动,利用SWAN模式模拟了太湖波浪场,结果表明:SWAN模式能够较好的模拟太湖波浪的生成与传播,适用于大型浅水湖泊(太湖);同时分析了该风场驱动下下太湖风浪谱,波浪的绝对频率主要集中在0.45～1.0 Hz的中高频率段;风向与波向具有高度一致性.在同一风速下,太湖不同区域波浪成长稳定时间不同,湖心区稳定的谱峰频率在0.342～0.585 Hz之间,湾区及西山岛附近狭长水域稳定的谱峰频率在0.447～0.765 Hz之间;在同一区域,风速增大,波浪稳定时间减少,谱峰频率沿低频推移,在湖心区谱峰频率最小不低于0.340 Hz,湾区、西山岛附近狭长水域最小不低于0.447 Hz;风向的改变对湾区及西山岛附近狭长水域的波浪频谱形状影响较大.

Wave fields in Lake Taihu are simulated using the wave model SWAN through inputting the actual uniform wind field data. The results show that SWAN model can simulate the wave generation and propagation of Lake Taihu well and is suitable for Lake Taihu. The study also found that the absolute wave frequency is mainly concentrated in the high frequency 0.45-- 1.00 Hz by analyzing the wave spectrum in Lake Taihu, and there is a high consistency between the wind and waves. On the condition of the same wind speed, the time for wave growing into stable wave is different by regions. The peak absolute wave frequency in the cen- tral lake is between 0. 342 Hz and 0. 585 Hz when it becomes steady, while in the bay area and narrow area around Xishan Island, between 0. 447 Hz and 0. 765 Hz. On the condition of the same region, with the increase of wind speed, time for wave getting sta- ble reduces and the peak absolute wave frequency moves toward the low frequency. The peak ＇absolute wave frequency in the central lake is no less than 0. 340 Hz, and in the bay area and narrow area around Xishan Island, no less than 0.447 Hz. In addition, the change of wind direction has a greater impact on the shape of the wave spectrum in the bay area and narrow area around Xishan Island.