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将由波浪作用下的细颗粒沉积物沿岸搬运而得到的计算公式 ,用于研究在波浪、沉积物性质和海底斜坡影响因素下悬浮物质垂直海岸的分布情况。公式主要应用于两个区域 :一是用于破浪带即从海岸带到破波带 ,二是用于从破波带向海到波折区。任何地方的悬浮沉积物浓度主要由底质沉积物的侵蚀或携带和侵蚀物质的沉降平衡来决定。这个公式已经应用于有沿岸流和悬浮物集中的三角洲盆地和中国黄海的连岛地区。如果能更好地掌握海底泥沙在海滩剖面上的侵蚀和搬运规律 ,这个公式可能更完善。1 计算公式悬浮沉积物单位时间垂直海岸的平均搬运速率即卸载… 相似文献
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假定条件为浅水 ,波倾角小 ,并具有崩顶破浪现象。在破浪带由于反射波的能量增强而使入射波发生分散 ,使反射波能能够保存 ,在护岸前面形成部分持续波 ,引起辐射应力和底部应力的调制 ,从而导致波浪增水、沿岸流及沿岸沉积物的搬运。在较宽的破浪带形成的大量持续波会导致海滩坡度变缓 ,使调制的影响增强。总的水深坡度 (包括波浪增水 ) ,有护岸海滩比没有护岸的海滩要陡 ,沿岸流和沿岸的沉积物搬运受海堤垂岸位置的影响强烈 ,在坡度较陡的海滩上 ,总的沉积物的运移要小于自然海滩 ,而坡度较缓的海滩由部分持续浪造成的调制将非常重要 ,其输… 相似文献
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非结构化网格下大范围波生流模拟和应用 总被引：1，自引：0，他引：1
波浪破碎引起的沿岸流是近岸海域的关键水动力因素。利用基于缓坡方程得到的光程函数方程和波作用守恒方程建立了考虑绕射效应的大范围波浪传播模型,模型可以考虑流场的影响;将波浪模型计算得到的辐射应力、波浪紊动系数等参数添加到三维水动力模型中,得到大范围近岸波生流的计算模型。模型中流场和波浪可以共用计算网格,且可同步耦合计算;模型基于非结构化网格,可以拟合复杂岸线的变化。模型对波生沿岸流、环流和逆流进行了验证,同时对实际海域的波生流进行了计算,结果表明:该模型对近岸波浪破碎引起的波生流具有很好的精度和适用性,可用于实际工程的计算。 相似文献
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基于非结构网格有限体积法的环流模型,建立了相位平均的波流作用模型。模型中考虑了波浪破碎效应的三维辐射应力和波流作用下的扩散系数。通过模拟试验水池中人工岛和天然岛屿周围的波生流,对岛周围波生流的运动特征进行了分析。当波浪垂直入射到均匀斜坡上的人工岛时,岛周围产生回流和对称的环流,流速沿水深分布稍有差异。在天然岛屿中,入射波浪在近岸形成沿岸流。靠近岸线岛屿周围的沿岸流比离岸较远岛屿周围的流速大。这和辐射应力在浅水区域作用有关,岸线区域波生流特征明显。近岸岛屿周围在波浪辐射应力下产生不同的波浪增水,该波浪增水形成压力梯度进而促进岛屿周围的流态变化。 相似文献
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对大连湾内部及外侧海域采集的46个表层沉积物进行了粒度分析,研究了大连湾现代沉积动力环境、沉积物运移、搬运方式及营力的空间差异,探讨了大连湾内外沉积物运移交换及其影响机制。大连湾内物质来源较少,湾外基岩海岸的侵蚀碎屑、外海潮流携带悬浮沙是本区沉积物的主要来源。岬角沿岸、三山岛周边海域长期波浪辐聚,形成高能扰动环境;三山岛外侧水道为强潮流冲刷环境,涨、落潮流流速上的差异导致双跃移组分;大连湾内潮流波浪较弱,沉积物以悬移组分为主。湾口近岸以波浪破碎形成的沿岸流为主要搬运营力,沉积物自老窝咀、棒棰岛沿岸向大连湾内输运;湾口的中北部物质的交换以潮流为主要搬运营力,向北运移进入大连湾北部。大连湾虽然内外物质的交换较弱,但却具有对来自北黄海物质的"捕获"作用,对于研究古黄海暖流的形成演化指示了新思路。 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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本文研究了近岸带内由于波浪破碎引起的沿岸流问题的数值解法,推导了适用于一维对流扩散方程的点点精确的 Petrov—Galerkin 有限元一般公式及其对权函数形式的要求,给出了四种权函数的初等表达式,得到了一种对沿岸流问题行之有效的计算格式。两个算例与传统格式相比较,都证实了这种格式具有明显的优越性。 相似文献
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文登近岸海域表层沉积物分布特征及影响因素 总被引：1，自引：0，他引：1
根据2013年文登近岸海域130个表层沉积物样品资料,分析了研究区表层沉积物分布特征,结合表层沉积物起动流速、波浪破碎水深和潮流数值模拟等资料,初步探讨了表层沉积物分布格局的影响因素。结果表明,研究区表层沉积物主要包括砂、粉砂、黏土质粉砂等8种类型,由岸向海粒径变细、分选变差。母猪河、昌阳河主要影响研究区东部沉积物的分布,黄垒河主要影响研究区西部沉积物的分布,河流的存在控制着研究区沉积物分布的基本格局。"波浪掀沙,潮流输沙"控制了表层沉积物的分异,形成了研究区中部颗粒较粗,东西两侧颗粒较细的沉积物分布规律。 相似文献
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Mobile sand deposits and shoreface sediment dynamics in the inner German Bight (North Sea) 总被引：1，自引：0，他引：1
This paper presents a conceptual model for the net bedload transport regime on the shoreface of the German Bight. The model is based on the spatial distribution of the surficial sediment cover (North Sea sands) which is identical to the uppermost layer in the seismic recordings. Sediment thickness was measured using very high resolution seismic profiling (chirp sonar) and vibrocoring. The three-dimensional sediment distribution was estimated using geostatistical methods (cokriging). The results demonstrate a longshore sand distribution with three distinct zones. In Zone 1 (0–10 m water depth) the sediments attain their maximum thickness of 10±2.5 m. Between 10 and 15 m water depth a relatively thin sand layer of 0.4–1.5 m is observed within Zone 2. The seaward adjacent Zone 3 (15–20 m water depth) is characterized by an averaged sand thickness of 2–3 m with local maxima of 5–6 m. Further offshore, the sand layer decreases to about 1–2 m thickness. The net bedload transport directions inferred from this sediment zonation comprise a longshore sediment bypassing in Zone 1 which results in a substantial sediment supply to the innermost part of the German Bight due to bedload convergence. Shore-normal bedload transport shifts sand to and fro across the coastal profile although the net directional transport is seawards. This results in sediment depletion between the 10 and 15 m-isobaths (Zone 2) and an adjacent sediment accumulation in deeper waters (Zone 3). 相似文献
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海南岛东南浅海表层沉积物粒度特征及沉积环境 总被引：1，自引：0，他引：1
对海南岛东南浅海377组表层沉积物样品(平均水深112.3 m)开展粒度测定及沉积物类型划分,并运用统计规律及沉积输运趋势分析,探讨了底质沉积物分布格局与物质来源及沉积动力环境关系。结果表明,海南岛东南浅海沉积物类型复杂,共分布13种沉积物类型,粒度组成以粉砂和砂为主,平均粒径均值为5.73Φ,优势粒级为细粉砂级(6~8Φ),分选差。不同海域沉积物粒径差异明显,北部近岸以含砾沉积为主,中部呈NE-SW向的砂质沉积区(水深80~120 m),西南近岸滨海、北中部海域以及东南部海域多为粉砂、黏土沉积。结合地理位置、沉积物源及水动力条件差异,研究区划分为3个沉积区:I区主要以含砾粗颗粒沉积为主,受控于海南岛上径流及强风浪作用,物质来源以万泉河等河流输运及岸线侵蚀物质为主,强动力(高能)沉积环境;II区以砂沉积为主,受到表层流及风浪等共同影响,可能主要是残留滨海沉积混入了海南岛径流及岸线侵蚀、少量珠江流域及外海复杂来源等现代细粒物质的混合沉积,中等动力沉积环境;III区以细粒沉积为主,主要受华南近岸流、风浪作用及南海暖流影响,推测物质来源主要为海南岛河流输入、岸线侵蚀及复杂外海来源细粒物质的加入,弱动力(低能)沉积环境。 相似文献
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In this paper, the water waves and wave-induced longshore currents in Obaky coastal water which is located at the Mediterranean coast of Turkey were numerically studied. The numerical model is based on the parabolic mild-slope equation for coastal water waves and the nonlinear shallow water equation for the wave-induced currents. The wave transformation under the effects of shoaling, refraction, diffraction and breaking is considered, and the wave provides radiation stresses for driving currents in the model. The numerical results for the water wave-induced longshore currents were validated by the measured data to demonstrate the efficiency of the numerical model. Then the water waves and longshore currents induced by the waves from main directions were numerically simulated and analyzed based on the numerical results. The numerical results show that the movement of the longshore currents was different while the wave propagated to a coastal zone from different directions. 相似文献
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Sediment is being transported from the Nile Delta to the Israeli coast by a wave-induced longshore current carrying mainly sand, and by the geostrophic Mediterranean Current, detected in Earth Resources and Technology Satellite (ERTS) photographs through the presence of suspended sediments. The location of these suspended sediments is consistent with computations of the maximum depth of wave stirring on the shelf. Since the construction of the Aswan Dam in 1965, sand has been more than adequately supplied by the severe erosion of the Nile Delta beaches. No changes in the longshore transport of sediment along the Israeli coast are anticipated from the Aswan Dam for a few hundred years.In memory of O. H. Oren, a pioneer in the study of the Nile flood along the Israeli coast. 相似文献
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Calculation of longshore sediment transport 总被引：1，自引：0，他引：1
I. O. Leont’yev 《Oceanology》2014,54(2):205-211
Calculation approaches to longshore transport of sandy sediments are discussed. The estimation of the total sediment transport rate is shown to be possibly based on the so-called CERC formula, where the proportionality factor K should be calculated from relationships of Bayram et al. [8] or Leont’yev [4]. In both cases, the results are very close to each other if the author’s determination of the wave breaking depth is used. Under the condition of contrasting variations in the sediment grain size over the coastal profile or in the case of fragmentary sand distribution on the surface of the bed, the local approach implying process-based modeling is more effective. A model is suggested to compute the local longshore sediment transport rates. 相似文献
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Ephemeral sand waves in the hurricane surf zone 总被引：2，自引：0，他引：2
Andrew B. Kennedy K. Clint Slatton Tian-Jian Hsu Michael J. Starek Kittipat Kampa 《Marine Geology》2008,250(3-4):276-280
Airborne bathymetric LIDAR observations along the Florida panhandle after Hurricane Dennis (2005) show the first unequivocal observations of surf-zone sand wave trains.
These are found in depths of 5m along the trough of the hurricane bar, where hindcasts show strong longshore currents only during severe storms. The waves extend over tens of kilometers of coast after Dennis but are absent from the same area in four other datasets. Observed wavelength to water depth ratios are comparable to river dunes and tidal sand waves but height to depth ratios are smaller, with the largest wave heights around 0.1 times the water depth. The sand wave generation mechanism is hypothesized to be from wind-and-wave-induced longshore currents, which were hindcast to be large during Dennis, with destruction from water wave orbital velocities. 相似文献
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黄河三角洲孤东海域沉积物及水动力 总被引：7，自引：0，他引：7
根据黄河三角洲孤东近岸海域表层沉积物取样、水文泥沙观测和风浪资料推算,分析沉积物特征和运移趋势,并通过水动力条件(潮流和波浪)探讨沉积物起动和输移特征。结果表明,孤东海域沉积物多为粉砂类物质,由内向外逐渐变细,分选变差,丁坝的修建对周围粒径分布影响明显;沉积物运移趋势受风成余流、岸线轮廓和丁坝工程修建的影响,不同区域表现为不同的输移方向;研究区水动力表现为波浪掀沙、潮流输沙的特征,由于潮流较小,不足以引起泥沙的起动,泥沙起动主要由波浪引起。 相似文献
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A unique Yellow River-derived distal subaqueous delta in the Yellow Sea 总被引：11，自引：0，他引：11
Newly acquired high-resolution Chirp sonar profiles reveal a unique Yellow River-derived, alongshore distributed, bidirectional (landward and seaward) across-shelf transported, omega-shaped (“Ω”) distal subaqueous deltaic lobe deposited around the eastern tip of the Shandong Peninsula in the Yellow Sea. This clinoform deposit directly overlies the postglacial transgressive surface, featured by convex-up seafloor morphology, up to 40 m thick locally. Radiocarbon-14 dates from the underlain pre-Holocene and transgressive sediments indicate this distal lobe has formed since the middle-Holocene highstand under a relatively stable sea level. This along-shelf distributed distal clinoform has been deposited mainly by the resuspended Yellow River sediments carried down by the coastal current, interacting with the local waves, tides and upwelling. Collectively, over the past 7000 years, nearly 30% of the Yellow River-derived sediment has been re-suspended and transported out of the Bohai Sea into the Yellow Sea. Overall, the Yellow River-derived sediment could reach the − 80 m water depth in the central South Yellow Sea, about 700 km from the river mouth; in contrast, a very small fraction of the modern riverine sediment could escape the outer shelf or reach the Okinawa Trough. 相似文献