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岬湾相间的琼州海峡南岸在海岸动力条件作用下,岸滩发生侵蚀或堆积,特别是南岸中部的南渡江三角洲沿岸岸滩演变剧烈。该文从海岸动力地貌的角度,对琼州海峡南岸的海岸动力特征、泥沙运动以及岸滩演变进行分析。根据海峡南部三维潮流场数值模拟结果,结合经验公式初步分析潮流引起的泥沙运移速率和方向,得到岸外水域总的泥沙运移趋势为从西向东。根据波浪动力计算分析沿岸泥沙运移,探讨沙质岸滩的动态与地貌演变之间的关系,得出海峡南岸海岸地貌演变与盛行的NE和NNE向风浪有密切关系,岸滩的演变过程主要受制于这两个方向的风浪及其引起的泥沙沿岸运移。 相似文献
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琼州海峡南岸海岸动力地貌研究 总被引：6，自引：0，他引：6
岬湾相间的琼州海峡南岸在海岸动力条件作用下,岸滩发生侵蚀或堆积,特别是南岸中部的南渡江三角洲沿岸岸滩演变剧烈。该文从海岸动力地貌的角度,对琼州海峡南岸的海岸动力特征、泥沙运动以及岸滩演变进行分析。根据海峡南部三维潮流场数值模拟结果,结合经验公式初步分析潮流引起的泥沙运移速率和方向,得到岸外水域总的泥沙运移趋势为从西向东。根据波浪动力计算分析沿岸泥沙运移,探讨沙质岸滩的地貌演变之间的关系,得出海峡南 相似文献
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本文通过山东半岛海岸地貌类型与沿岸波浪、潮汐发生学关系的对比分析,引入浪潮作用指数 K,K=2.5×(H/R),H 为平均波高,R 为平均潮差.K>1时,海岸地貌演变的动力以波浪作用为主,海岸极少发育潮汐叉道和落潮三角洲,但连岛坝发育较好;K<1时,海岸地貌演变的水动力以潮汐作用为主,落潮三角洲、潮汐叉道较发育;K 值接近于1时,发育潟湖等过渡海岸地貌类型. 相似文献
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海南岛南渡江三角洲北部沿岸的泥沙转运和岸滩运动 总被引：3，自引：0，他引：3
南渡江三角洲海岸可分为东部废弃侵蚀岸，北部泥沙转运岸西部淤涨堆积岸等三个岸段，北部岸段为了边接东、西部岸段，存在大规模的，有节奏的沿岸泥沙向西和向岸转运及其相应的岸滩运动现象，涨沙主要来自南渡江干流河口及其以东的废弃侵蚀岸。文中还结合对北部岸河口和沿岸泥沙转运规律的分析，讨论了波浪优势型河口三角洲特征及其堡岛海岸的形态、动态和泥沙来源以及人类活动对该岸段的影响等问题。 相似文献
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基于历史海图、历史时期卫星遥感影像、2019年实测水下地形和潮流、波浪数值模拟成果,研究该海域岸滩的发育演变背景、海床和岸线自然冲淤动态、动力泥沙环境及岸滩冲淤动力机制。采用LITLINE岸线演变数学模型,模拟计算了不同离岸距离和不同平面形态人工岛布置型式对近岸岸线变形的影响,岸滩泥沙动力机制和岸滩演变趋势表明,人工岛实施后近岸最大潮流流速小于近岸泥沙起动流速,不具备起动近岸岸滩泥沙的基本条件; SSE向波浪作用时,人工岛西北侧波高明显减弱,波向西偏; S向波浪作用时,人工岛北侧波高明显减弱; SSW向波浪作用时,人工岛东北侧波高明显减弱,波浪传播方向东偏;波浪场改变后人工岛掩护区东西两侧岸滩附近泥沙分别具有向东和向西运移至人工岛掩护区的趋势,形成掩护区的淤积和东西两侧岸线冲刷。 相似文献
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DELFT 3D在离岸人工岛建设中的应用——以海南岛万宁日月湾人工岛为例 总被引：1，自引：0，他引：1
离岸建设人工岛是围填海的重要方式之一。人工岛的建设势必改变工程区的水动力条件、泥沙输运格局与海岸演变状况。选取合理的平面布置方案,减少工程建设对海岸环境的负面影响,是人工岛建设能否成功的关键因素。以海南岛万宁日月湾人工岛建设为例,利用DELFT 3D模型系统,研究原场与不同平面布置方案后的波浪传播、波生流、泥沙输运与岸滩演变,探讨不同人工岛方案岛后形成连岛坝(Tombolo)或突出体(Salient)的可能性及泥沙淤积体积的大小,分析不同方案的优劣。研究表明,不同人工岛方案因为其大小、离岸距离及所处位置的差异,对岛后的波浪传播、波生流、泥沙输运与地形冲淤演变产生不同的影响。人工岛离岸距离越远、所处位置水深越大,人工岛在波峰线上的投影长度越短,形成连岛坝的可能性越小。 相似文献
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近岸波、流作用下结构物附近海岸演变的数值模拟 总被引：5，自引：0，他引：5
针对与砂质海岸在波浪作用下的演变有关的波浪、近岸流及输沙问题进行了系统的研究,并对结构物附近海岸演变进行了数值模拟。考虑了波浪折射-绕射及波浪破碎的综合作用,在近岸流场的模拟中用沿水深积分形成的K方程模型确定涡粘系数。计算岸滩地形变化时,综合波浪、近岸流作用的底沙和悬沙输沙率,并考虑波浪对泥沙作用的影响。模型对防波堤和近岸沉船附近地形变化进行了模拟,效果良好。 相似文献
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I~crIOWIn the coastal area, especially at the sandy seashore, wave and nearshore current are the major factors which affect sediment transPOrt and the motyhChdynamics.The numerical models of predicting the beach evolution can be classified intO the medi~term and long-term models according to their space and time scales (De Briend et al., 1993;Watanabe, 1990; Watanabe et al., 1986; Tao, 1996). In the medium-term model the effects ofwave, nearshore current and sediment transport are conside… 相似文献
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Accurate prediction of longshore sediment transport in the nearshore zone is essential for control of shoreline erosion and beach evolution. In this paper, a hybrid Adaptive-Network-Based Fuzzy Inference System (ANFIS), Fuzzy Inference System (FIS), CERC, Walton–Bruno (WB) and Van Rijn (VR) formulae are used to predict and model longshore sediment transport in the surf zone. The architecture of ANFIS consisted of three inputs (breaking wave height), (breaking angle), (wave period) and one output (longshore sediment transport rate). For statistical comparison of predicted and measured sediment transport, bias, root mean square error and scatter index are used. The longshore sediment transport rate (LSTR) and wave characteristics at a 4 km-long beach on the central west coast of India are used as case studies. The CERC, WB and VR methods are also applied to the same data. Results indicate that the errors of the ANFIS model in predicting wave parameters are less than those of the empirical formulas. The scatter index of the CERC, WB and VR methods in predicting LSTR is 51.9%, 27.9% and 22.5%, respectively, while the scatter index of the ANFIS model in the prediction of LSTR is 17.32%. A comparison of results reveals that the ANFIS model provides higher accuracy and reliability for LSTR estimation than the other techniques. 相似文献
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根据１９９０年现场调查及前期观察资料，论述了海南岛新海弧形海湾不同岸段由主要动力驱动过程和海滩地貌结构组成的４种海滩地貌状态，为Ⅰ．隐蔽段消散类型，Ⅱ．脊－沟体系与低潮台地类型，Ⅲ．韵律海滩与砂坝类型，Ⅳ．开敞段消散类型。应用泥沙粒级参数概率模型分析近岸泥沙纵向运动趋势，结果表明，常波况下，沿岸泥沙存在双向运动，湾顶海滩为汇集地带，泥沙纵向运动主趋势为西南向；高能条件下，海岸北段可出现北向泥沙运动 相似文献
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Natural beaches tend to exhibit an equilibrium profile that is planar nearshore and nonplanar, concave-up offshore. The longshore current on this type of beach profile depends on the horizontal distance to the location of the intersection between the planar and nonplanar profiles. As the width of the planar beach face decreases, the location of the maximum longshore current moves closer to the shore. The dependency of the corresponding longshore sediment transport rate on the location of the intersection between the two profiles is demonstrated for two energetics-based sediment transport models. Again, a narrower beach face results in the maximum sediment transport being closer to the shore. Total sediment transport rates are also a function of the planar beach face width. This suggests that longshore transport rates are modulated by the tidal elevation. 相似文献
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《Coastal Engineering》2001,42(3):199-218
A large-scale laboratory facility for conducting research on surf-zone sediment transport processes has been constructed at the U.S. Army Engineer Research and Development Center. Successful execution of sediment transport experiments, which attempt to replicate some of the important coastal processes found on long straight beaches, requires a method for establishing the proper longshore current. An active pumping and recirculation system comprised of 20 independent pumps and pipelines is used to control the cross-shore distribution of the mean longshore current. Pumping rates are adjusted in an iterative manner to converge toward the proper settings, based on measurements along the beach. Two recirculation criteria proposed by Visser [Coastal Eng. 15 (1991) 563] were also used, and they provided additional evidence that the proper total longshore flow rate in the surf zone was obtained. The success of the external recirculation system and its operational procedure, and the degree of longshore uniformity achieved along the beach, are the subjects of this paper. To evaluate the performance of the recirculation system, and as a precursor to sediment transport experiments, two comprehensive test series were conducted on a concrete beach with straight and parallel contours (1:30 slope), one using regular waves and the other using irregular waves. In the regular wave case, the wave period was 2.5 s and the average wave height at breaking was approximately 0.25 m. In the irregular wave case, the peak wave period was 2.5 s and the significant breaking wave height was approximately 0.21 m. The longshore current recirculation system proved to be very effective in establishing uniform mean longshore currents along the beach in both cases. This facility and the data presented here are unique for the following reasons: (1) the high cross-shore resolution of the recirculation system and the ease with which changes can be made to the longshore current distribution, (2) the degree of longshore uniformity achieved as a percentage of the length of the basin (even near the downdrift boundary), (3) the scale of the wave conditions generated, and (4) the relatively gentle beach slope used in the experiments (compared to previous laboratory studies of the longshore current). Measured data are provided in an appendix for use in theoretical studies and numerical model development and validation. 相似文献
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本文结合毛里塔尼亚友谊港下游冲刷模型的试验研究探讨了海岸波浪动床模型的相似律和试验波浪要素的确定。作者推导获得了同时满足波浪作用下岸滩剖面冲淤相似、沿程冲淤部位相似、泥沙起动相似和沉降相似的综合相似比尺公式：λρｓ－ρ＝λ＾１／３ｌ．λ＾１／６Ｄ；λｄ＝（λＤ／λｔ）＾２／３解决了波浪冲刷动床模型的基本相似问题和砂的选砂问题。对于常浪向与强浪向不一致的海岸，作者提出了采用综合考虑波高、波周期（或波 相似文献
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A numerical model of beach morphological evolution due to waves and currents in the vicinity of coastal structures 总被引：2，自引：0，他引：2
A numerical model was developed of beach morphological evolution in the vicinity of coastal structures. The model includes five sub-models for random wave transformation, surface roller development, nearshore wave-induced currents, sediment transport, and morphological evolution. The model was validated using high-quality data sets obtained during experiments with a T-head groin and a detached breakwater in the basin of the Large-scale Sediment Transport Facility at the Coastal and Hydraulics Laboratory in Vicksburg, Miss, USA. The simulations showed that the model reproduced well the wave conditions, wave-induced currents, and beach morphological evolution in the vicinity of coastal structures. Both salient and tombolo formation behind a T-head groin and a detached breakwater were simulated with good agreement compared to the measurements. 相似文献