黄河三角洲北部海域大风过程泥沙运动及其动力机制数值模拟研究
发布时间：2018-11-08 20:11
【摘要】：黄河三角洲北部海域6级以上大风频发，寒潮大风期间，由于风暴潮与天文大潮叠加造成水位暴涨，同时在大风浪的作用下，海岸侵蚀、码头防波堤垮塌等事故极易发生，造成巨大的经济损失。在极端海况下泥沙运动异常活跃，骤冲骤淤频发，造成石油平台、管道的破坏及航道、港池的淤积。因此对极端海况下泥沙运动及其动力机制的研究是非常重要的。本文系统地分析了风在风暴潮、波浪、冲淤等方面起到的重要作用，对于寒潮大风期间的灾害预警和海岸工程的防护具有一定的实践意义。 本文以中心二号平台实测风资料为输入条件，建立了整个渤海海域的风暴潮模型和波浪模型，并结合大风过程的实测风、潮位、海流、波浪资料分析了大风对于水动力的影响。结果表明：①黄河三角洲北部海域E向、N向风引起增水，S向、W向风引起减水；当风与流速方向一致时，流速增大，当风与流速方向相反时，流速减小；偏E、NE风存在较长的风区可以在该海域产生较大的波浪。②在SW风的影响下，研究海域发生了减水现象，减水幅度均为0.3m左右，在E向风的作用下黄河三角洲北部海域内剧烈增水,增水幅度可达0.8m-1m，增水等值线呈南北向分布，且西侧增水值大于东侧；在E风作用下，研究海域落潮流优势明显；不论在E、NE风作用下，还是在W风、NW风作用下，波浪均呈从东向西逐渐变小的趋势，浅水区波浪等值线近似平行于等深线，但是E、NE风导致研究海域波浪较大，有效波高可达2.4m左右。 本文分析了实测悬沙数据与波浪、潮流的相关关系，同时进行了黄河口附近海域悬沙分布和冲淤的计算，结果显示：①研究区悬沙浓度时间分布主要受波高的控制，悬沙空间分布由潮流和波浪两个因素控制，波流共同作用下悬沙高值中心与纯潮流悬沙高值中心基本对应，但悬沙浓度有较大程度的提高。②2013年4月份E风频发，实际冲淤受波浪影响较大，其中清水沟入海口附近冲刷量具有了较大程度的提高，同时黄河三角洲北部海域也有两方面的变化：一是5m等深线附近出现一个侵蚀中心，月冲刷量为0.02m以上，二是侵蚀中心南侧近岸处出现冲刷。 一个大风过程前后实测沉积物粒度特征显示，大风使位于1.5m—4m等深线之间南北向分布4个采样点沉积物变细，这种现象主要由研究区内偏E向风及测线处流场特征造成的：偏E向风导致泥沙以沿岸运动为主，而流速在测线处的降低导致了粉砂粒级沉积物的沉降，，使沉积物变细。
[Abstract]:In the northern waters of the Yellow River Delta, strong winds of Grade 6 or above occur frequently. During the period of cold high winds, the water level rises sharply due to the superposition of storm surges and astronomical tides. At the same time, under the action of the heavy wind and waves, coastal erosion and breakwater collapse at the wharf are very easy to occur. Causing enormous economic losses. Under extreme sea conditions, sediment movement is very active, sudden erosion and sudden siltation occur frequently, which results in the destruction of oil platform, pipeline and channel, as well as the siltation of harbor pool. Therefore, it is very important to study the sediment movement and its dynamic mechanism under extreme sea conditions. This paper systematically analyzes the important role of wind in storm surge, wave, scour and silt, etc., which has certain practical significance for early warning of disasters during cold wave and strong wind and protection of coastal engineering. In this paper, the storm surge model and wave model of the whole Bohai Sea are established on the basis of the measured wind data from the Central platform No. 2, and the effect of strong wind on hydrodynamics is analyzed by combining the measured wind, tide level, current and wave data of the gale process. The results show that: (1) in the northern Yellow River Delta, E, N, S and W directions cause water increase, and the velocity increases when the wind is in the same direction as the velocity of velocity, and decreases when the wind is opposite to the direction of the velocity of velocity; Under the influence of SW wind, the phenomenon of water reduction occurs in the study area, and the range of water reduction is about 0.3 m. Under the action of E-wind, the water increase in the northern waters of the Yellow River Delta can be as high as 0.8m-1m.The water increment isoline is distributed in the north-south direction, and the increase value in the west side is larger than that in the east side. Under the action of E wind, the advantage of the tidal current in the study area is obvious. Under the action of NE wind, W wind and NW wind, the waves tend to decrease gradually from east to west, and the wave isolines in shallow water are approximately parallel to the isobath, but the waves in the studied sea area are larger. The effective wave height is about 2.4 m. In this paper, the correlation between measured suspended sediment data and wave and tidal current is analyzed. At the same time, the suspended sediment distribution and scour and deposition in the waters near the Yellow River estuary are calculated. The results show that: 1 the time distribution of suspended sediment concentration in the study area is mainly controlled by wave height. The spatial distribution of suspended sediment is controlled by two factors: tidal current and wave. Under the action of wave and current, the suspended sediment height center corresponds to the pure tidal current suspended sediment height center, but the suspended sediment concentration increases to a large extent. The actual scour and siltation are influenced by the waves, and the scour amount near the mouth of the clear water ditch has been increased to a great extent, and there are two changes in the northern waters of the Yellow River Delta: one is that there is an erosion center near the 5m isobath. The amount of monthly scour is more than 0.02 m, and the second is erosion near the south side of the erosion center. The grain size characteristics of sediments measured before and after a strong wind process showed that the strong wind thinned the sediments of the four sampling sites located between the 1.5m-4m isobath and the north-south direction. This phenomenon is mainly caused by the characteristics of the flow field along the deviated E-direction wind and the measured line in the study area. The eolian wind causes the sediment to move mainly along the coast, while the decrease of the velocity of velocity in the measured line leads to the sedimentation of silt-sand sediment and the thinning of the sediment.
【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;TV148
本文编号：2319552
[Abstract]:In the northern waters of the Yellow River Delta, strong winds of Grade 6 or above occur frequently. During the period of cold high winds, the water level rises sharply due to the superposition of storm surges and astronomical tides. At the same time, under the action of the heavy wind and waves, coastal erosion and breakwater collapse at the wharf are very easy to occur. Causing enormous economic losses. Under extreme sea conditions, sediment movement is very active, sudden erosion and sudden siltation occur frequently, which results in the destruction of oil platform, pipeline and channel, as well as the siltation of harbor pool. Therefore, it is very important to study the sediment movement and its dynamic mechanism under extreme sea conditions. This paper systematically analyzes the important role of wind in storm surge, wave, scour and silt, etc., which has certain practical significance for early warning of disasters during cold wave and strong wind and protection of coastal engineering. In this paper, the storm surge model and wave model of the whole Bohai Sea are established on the basis of the measured wind data from the Central platform No. 2, and the effect of strong wind on hydrodynamics is analyzed by combining the measured wind, tide level, current and wave data of the gale process. The results show that: (1) in the northern Yellow River Delta, E, N, S and W directions cause water increase, and the velocity increases when the wind is in the same direction as the velocity of velocity, and decreases when the wind is opposite to the direction of the velocity of velocity; Under the influence of SW wind, the phenomenon of water reduction occurs in the study area, and the range of water reduction is about 0.3 m. Under the action of E-wind, the water increase in the northern waters of the Yellow River Delta can be as high as 0.8m-1m.The water increment isoline is distributed in the north-south direction, and the increase value in the west side is larger than that in the east side. Under the action of E wind, the advantage of the tidal current in the study area is obvious. Under the action of NE wind, W wind and NW wind, the waves tend to decrease gradually from east to west, and the wave isolines in shallow water are approximately parallel to the isobath, but the waves in the studied sea area are larger. The effective wave height is about 2.4 m. In this paper, the correlation between measured suspended sediment data and wave and tidal current is analyzed. At the same time, the suspended sediment distribution and scour and deposition in the waters near the Yellow River estuary are calculated. The results show that: 1 the time distribution of suspended sediment concentration in the study area is mainly controlled by wave height. The spatial distribution of suspended sediment is controlled by two factors: tidal current and wave. Under the action of wave and current, the suspended sediment height center corresponds to the pure tidal current suspended sediment height center, but the suspended sediment concentration increases to a large extent. The actual scour and siltation are influenced by the waves, and the scour amount near the mouth of the clear water ditch has been increased to a great extent, and there are two changes in the northern waters of the Yellow River Delta: one is that there is an erosion center near the 5m isobath. The amount of monthly scour is more than 0.02 m, and the second is erosion near the south side of the erosion center. The grain size characteristics of sediments measured before and after a strong wind process showed that the strong wind thinned the sediments of the four sampling sites located between the 1.5m-4m isobath and the north-south direction. This phenomenon is mainly caused by the characteristics of the flow field along the deviated E-direction wind and the measured line in the study area. The eolian wind causes the sediment to move mainly along the coast, while the decrease of the velocity of velocity in the measured line leads to the sedimentation of silt-sand sediment and the thinning of the sediment.
【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;TV148
【引证文献】
相关博士学位论文 前1条
1 王虎;波浪作用下黄河三角洲海床失稳机制与评价方法[D];中国海洋大学;2015年
本文编号：2319552
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