【作者】 郑运霞；

【导师】 韩树宗；

【作者基本信息】 中国海洋大学 ， 物理海洋， 2008， 硕士

【摘要】 海岸、河口区属于海洋与陆地相互作用的区域,潮汐、淡水径流、波浪的变形、折绕射、破碎等各种动力因素共同产生作用,构成了海岸、河口区域复杂的动力系统,控制着海岸、河口区的泥沙输运。由于海岸、河口区域水深较浅,波浪影响显著,因此同时考虑波浪和潮流这两个因素共同作用对研究海岸、河口区的悬浮泥沙输运是十分必要的。在有风浪的情况下,悬沙浓度分布情况会存在显著改变,为研究波浪尤其是风暴浪对悬浮泥沙的影响,本文主要进行以下工作:首先,运用改进的椭圆形台风风场模型,结合9711号天气过程的移动路径、中心气压等台风要素,成功模拟了台风所经地带风场、气压场的变化过程。经与实测资料对比验证了模式的精度;其次,将椭圆形风场模型计算的风场条件输入到SWAN波浪模型,采用三级嵌套的方法成功模拟了日照海区的波浪场,得出9711天气过程中的有效波高和周期等波浪要素的发展变化过程,并与实测资料进行验证;再次,运用COHERENS三维水动力模式,采用三级嵌套模型计算了日照近海的潮汐、潮流、风暴潮过程并与实测资料进行对比,验证了模式的可靠性。最后,为探求波浪作用对悬沙运动规律的影响,以经过验证的水动力场作为背景场,运用COHERENS-SED三维水动力悬沙模式,对日照海域的悬沙浓度分以下三种情况进行了模拟:1)考虑潮流和风暴浪过程;2)仅考虑潮流;3)考虑累年平均波要素和一般天气情况(累年平均风场、标准大气压)。得到以下结论:与单纯潮流作用相比,在有风浪的情况下,悬沙浓度分布情况会存在显著改变,整个海区总体含沙量大幅提高,在近岸区域尤为显著。考虑潮流、一般波浪和天气因素共同作用下的水体悬沙浓度比仅潮流作用下增大40%～100%。考虑9711号天气过程产生的台风浪作用下的水体悬沙浓度则比一般波浪和天气因素作用条件下增大约4倍。可见波浪是掀沙的重要动力过程,其对模拟结果影响很大,在悬沙输运数值模拟中为不可忽略的动力因素。更多还原

【Abstract】 Coastal and estuary regions are such regions where the interaction between land and sea is obvious and sediment is an important factor in coastal engineering research. Coastal and estuary regions are characterized by intensive interaction among wave, current, river runoff and so on. Its dynamic conditions which control the transport of suspended sediment are complicated and variable. The effect of wave (refraction, break up et al.) is very distinct in shallow water, such as the coastal and estuary zone. Therefore, the simulation of sediment with wave and current as well as their mutual interaction in coastal and continental shelf is necessary. The concentration of suspended sediment will be changed remarkably under the wind wave. A lot of effort has been made to study the impact of the wind wave on the suspended sediment, especially the one of storm wave.The major contents of this dissertation are shown as follows:1. The wind field and air pressure are simulated successfully with elements (path, center air pressure et al.) of No.9711 tropic storm using the improved elliptic wind model, and it’s proved that the model works well by comparing the wind speed and air pressure of simulated ones with the observed ones.2. Using the wind speed obtained in last process as input data, the wave field of considering area is simulated by SWAN (Simulating WAves Nearshore) model employing third class nesting. And the wave elements (Hs, T et al.) of No.9711 tropic storm can be computed.3. The hydrodynamic elements are simulated by the 3-D COHERENS model, and the modeled results of water surface elevation and current in offshore area of Rizhao are compared with the measured ones by Ocean University of China in August, 2005. The COHERENS model simulated the elements over the offshore region of Rizhao realistically.4. To check degree of impact on the concentration of suspended sediment caused by wind wave, a 3-D COHERENS-SED model is established based on the validated COHERENS model. The suspended sediment is simulated under the following three conditions: 1) driven by the No.9711 tropical storm; 2) driven only by astronomic tides; 3) driven by normal condition (year by year averaged wind elements and the standard air pressure). The major conclusions of this dissertation are shown as follows:When the model is driven by both wind and tide, the concentration is much bigger than that only driven by astronomic tides (the increase is about 40%~100%), especially along the coast. When No.9711 tropical storm is taken into account, the concentration is 4 times thicker than that under the normal condition. So wind wave plays an important part in changing the suspended sediment concentration.更多还原