The Numerical Simulations Of Typhoon Wave's Propagation And Development In China's Internal Sea

Typhoon waves became a hot topic in the ocean dynamic field these days. Typhoon swell has great influence on the vessels both at sea and moored. Energy of swells can propagate from deep ocean to the offshore. Few researches are made on the wave feature and generation of long waves during the propagation. Based on the spectral wave model, a typhoon wave simulation aiming on China's internal sea is set up. The model results in a suitable one after calibration the wind model and the wave model. White capping, bottom friction and the other source functions are investigated on the effect of waves both in deep ocean and swallow near shore. Three typical typhoons are simulated using the model. The paper focus on the propagation and development of typhoon waves which is from the southeast sea to the Huanghai Sea and Bohai Sea, and investigate the propagation, development parameters, influence sphere and influence degree in the focus area. Cognitions are concluded as follows:(1) Through the verification, it is certificated that the typhoon wave model for China's internal sea is suitable for analyzing the propagation and the development of typhoon waves from the southeast sea to the Huanghai Sea and Bohai Sea. Numerical experiments show that white capping has great influence in the wave simulation with great water depth, while small influence in swallow water. Concerning about the bottom friction, it has equal influence with either water depth.(2) Typhoon waves are restricted by typhoon speed, wind influencing period, typhoon moving velocity etc. Changing of typhoon route has little to do with the wave height in the deep ocean, but plays an important role in the near shore.(3) Generalizing the influence of three typical routes, we can see that: the typhoon landing at Taiwan, Fujian and Zhejiang province affected the landing region and has limited influence in the north of Yangtze River; after the typhoon waves spread to the north of Huanghai Sea-North of Jiangsu province, seashore of Shandong and the Bohai sea, the signal wave height(Hs) became smaller. A common conclusion is drawn that in the north of Huanghai Sea-North of Jiangsu province Hs=2-3m; outside Shandong and the Bohai River internal sea Hs=l-2m; inside the Bohai sea Hs<1. (4) After the landing of typhoon, the typhoon waves generated by the first and the second route has an energy transformation from the height frequency to the low which can cause long waves. Both the typhoon waves can propagate to the Bohai Sea. The third typhoon waves'energy may unfinished the transfer because of the high moving speed of typhoon center, which needs more investigation in the future.(5) After the generation of long waves, the wave energy's attenuating became slower. The long waves'existence in the north of China sea can last at least 2 days. The paper focus on the waves with periods from 10s to 30s, during which long waves can easily resonate with the vessels.(6) The typhoon swells travel fast before landing, at a certain velocity between 50km/h and 60km/h, which is almost twice of the moving speed of typhoon center in China's internal sea.