胶州湾三维水动力数值模拟研究

发布时间：2018-08-03 13:20

【摘要】：本文使用无结构网格三维有限体积海洋模式FVCOM,建立了适用于胶州湾的三维正压高分辨率数值模型。通过观测与模拟资料的对比,验证了所建立模型的合理性。基于建立的模型,对胶州湾的潮汐潮流进行了精确的数值模拟,通过示踪试验探讨了胶州湾水交换的影响因素及特征,并基于胶州湾跨海大桥的实际桥长、桥墩数目和空间分布及桥墩的直径参数等调研数据,生成含大桥的高分辨率网格,对比研究胶州湾大桥建桥前后的水动力特征。主要得到以下几点结论：(1)研究了胶州湾的潮汐、潮流以及余流特性。模拟结果显示,潮流呈往复流特征。余流受到复杂地形作用,在湾口附近形成多涡旋结构。斯托克斯漂移的值比欧拉余流小一到两个量级,拉格朗日余流与欧拉余流基本一致。(2)利用断面的流量积分计算结果表明,海面起伏对纳潮量的影响最大可略大于1%,不可忽略：大潮时期的纳潮量为小潮时期的2-3倍；纳潮量春季最低,冬季其次,夏秋季较高。利用研究计算区域的水深及海面起伏计算的纳潮量的值较利用断面流量积分的结果普遍偏大,但季节变化的趋势两种方法基本一致。(3)胶州湾内不同子区域的水交换能力以及稳定时间均不同,湾西侧水交换能力较强,但达到稳定较慢：湾口水交换达到稳定较快,但质点容易被黄岛北部的涡旋对(余流涡)捕获,水交换能力偏低;湾东北部区域水交换能力弱,且主要通过湾东部沿岸区域与湾外发生水交换。涨潮期间放置示踪粒子稳定时间较短,落潮期间放置示踪粒子稳定时间较长。(4)大桥的建立后,桥的阻隔作用使落潮流在整个湾内除桥墩附近极小部分区域外堆积,水位最大增加1.5cm,且跨海大桥的北侧的增加量大于桥南侧,桥北侧以西北部与东北部的增加值最大。同样,桥的阻尼作用使涨潮流在湾内水位减小,该变化主要集中在桥北侧(尤其是西北部和东北部)。大桥的建立使大桥附近的余流明显加强,对湾口的四个强涡旋的大小和结构均没有明显影响。在大桥西段,桥南北两侧的余流强度均有所加强；大桥中段,南侧的余流强度基本没有变化,北侧明显减小；大桥东段,南侧的余流强度明显增强,北侧减小。胶州湾大桥的建立使得胶州湾内的纳潮量无论是在大小潮期间还是平均值均有所减小。(5)跨海大桥对潮流的影响主要集中在桥墩附近区域。对于大沽河航道桥附近海域,加入大桥后,潮流经过大桥前,流场基本不变,经过大桥后,桥墩后的流场明显减弱。另外,在该研究区域小桥墩对潮流的影响程度及范围均明显小于大桥墩,即桥墩对潮流的影响情况与桥墩的尺寸以及桥墩之间的距离有直接关系。对于桥墩种类更多,更为密集,构造更为复杂的红岛互通立交桥附近海域,桥对潮流的影响更为复杂。桥墩为矩形而非对称的圆形,其对潮流的影响情况与潮流经过桥墩时与桥墩的角度有直接关系,且潮流要连续经过多个桥墩,故桥对潮流的影响是诸多桥墩共同作用的结果。潮流第一次经过桥墩时,桥墩之间的流速明显增大,桥墩后流速减弱,经过后,流速整体减小,故再次经过桥墩时,桥墩后的流速再次减小,桥墩之间的流速较经过前增加,但较无桥时微弱减小。跨海大桥的建立对湾内不同区域的水交换能力影响不同,桥西北部海域的水交换能力明显减弱,而桥东北部海域的水交换能力加强,湾中心以及湾口附近的水交换变化能力变化不大。(6)胶州湾海域的水温具有明显的季节差异,且基本随太阳辐射变化。胶州湾湾口之外的水域,等温线整体呈现东北一西南走向,海水温度年际变化较小；湾内的等温线分布,多平行于等深线,在湾口及湾中央较小,沿岸海区较大。
[Abstract]:In this paper, a three-dimensional finite volume ocean model FVCOM with unstructured grid is used to establish a three-dimensional positive pressure high resolution numerical model for Jiaozhou Bay. Through the comparison of the observed and simulated data, the rationality of the model is verified. Based on the established model, the tidal currents in the Jiaozhou Bay are numerically simulated and the tracer test is carried out. The factors and characteristics of the water exchange in Jiaozhou Bay are examined. Based on the actual bridge length, the number of piers and the spatial distribution of the bridge pier and the diameter parameters of the pier in Jiaozhou Bay Bridge, the high resolution grid containing the bridge is generated, and the hydrodynamic characteristics of the bridge before and after the construction of the Jiaozhou Bay Bridge are compared. The main conclusions are as follows: (1) The tide, tidal current and residual current characteristics of Jiaozhou Bay are studied. The simulation results show that the tidal current is characterized by reciprocating flow. The residual current is subjected to complex topography, forming a multi vortex structure near the mouth of the bay. The value of Stokes drift is two orders of magnitude smaller than Euler's residual current, and Lagrange's residual current is basically the same as Eulerian residual current. (2) the flow product of the cross section is used. The results show that the maximum influence of the sea surface fluctuation on the tidal volume can be greater than 1%, which can not be ignored: the tidal volume of the tide period is 2-3 times that of the small tide period, the tidal volume is the lowest in spring, the second in winter and the higher in summer and autumn. The results are generally large, but the two methods of seasonal variation are basically the same. (3) the water exchange capacity and stability time of different subregions in Jiaozhou Bay are different, the water exchange ability of the west side of the bay is stronger, but the stability is relatively slow: the water exchange of the Bay mouth is stable and fast, but the quality point is easily captured by the vortex in northern Huangdao (Yu Liuwo) and water exchange. The capacity is low; the water exchange capacity of the northeast part of the bay is weak, and the water exchange is mainly through the coastal area of the east of the Bay and outside the bay. The stable time of the tracer particles is relatively short during the flood tide, and the stable time of the tracer particles is placed for a long time during the ebb tide. (4) after the establishment of the bridge, the bridge's barrier effect makes the tidal current very little near the bridge pier in the whole bay. The maximum increase of water level is 1.5cm, and the increase of the north side of the bridge is greater than that of the south side of the bridge. The north side of the bridge has the largest increase in the north-west and northeastern part. Similarly, the damping effect of the bridge reduces the water level in the bay. This change is mainly concentrated on the north side of the bridge (especially in the northwest and northeast). The bridge is built to make the bridge. The residual current in the vicinity of the bridge has no obvious influence on the size and structure of the four strong vortices in the bay mouth. In the west section of the bridge, the strength of the residual current in the north and south sides of the bridge has been strengthened; the residual current intensity of the middle section of the bridge is basically unchanged and the north side obviously decreases; the residual current intensity in the east section of the bridge is obviously enhanced and the north side decreases in Jiaozhou. The establishment of the bay bridge makes the tidal volume of the Jiaozhou Bay decrease in both the size and the average. (5) the influence of the cross sea bridge on the tidal current is mainly concentrated in the vicinity of the bridge pier. For the sea area near the Dagu river channel bridge, the flow field is basically unchanged after the bridge is passed through the bridge. After the bridge, the flow after the bridge is passed. The impact of the piers on the tide is obviously smaller than that of the bridge pier, that is, the influence of the pier on the tide is directly related to the size of the pier and the distance between the piers. The influence of the pier is a rectangular and asymmetrical circle. The influence of the bridge to the tide is directly related to the angle of the pier when the tide passes through the pier, and the tide must pass through a number of piers continuously, so the effect of the bridge on the tide is the result of the joint action of many piers. When the flow velocity is obviously increased and the velocity of the pier decreases after the bridge pier, the flow velocity decreases as a whole, so the velocity of the pier decreases again when the pier passes through the pier again. The flow velocity between the piers increases before the bridge, but decreases slightly than that before the bridge. The water exchange capacity of the bridge in the different regions of the bay is different, and the water exchange in the northwest of the bridge is different. The ability of water exchange in the sea area of the northeast of the bridge was strengthened, and the water exchange ability of the Bay Center and the bay mouth changed little. (6) the water temperature in the Jiaozhou Bay area has obvious seasonal difference, and basically changes with the solar radiation. The isotherm in the waters outside the bay of Jiaozhou Bay shows the north-east north-west direction and the sea temperature as a whole. The interannual variability is relatively small, and the isotherms in the Bay are mostly parallel to the isthmus, smaller in the middle of the Bay and the Bay, and larger in the coastal waters.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.2

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