共查询到17条相似文献，搜索用时 125 毫秒
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为明晰太湖风浪的空间分布及季节变化,在湖心区设立波浪观测站,利用其记录的波浪数据证明SWAN模型能够较好地模拟太湖风浪.基于所建模型,对2013年自然风场条件下太湖不同湖区风浪季节动态进行模拟分析,结果表明:受岸线、地形和岛屿等地理因素影响,大太湖的风浪总是最强,其有效波高均值为0.523 m;而东太湖风浪最小,有效波高均值为0.305 m.受盛行风场季节变化影响,太湖春、夏季有效波高均值明显大于秋、冬季.太湖波浪的能量主要来源于风场,其有效波高随风速增大而增大,两者呈极显著正相关.而风向则可以通过改变风区长度来影响风浪生消.在偏东风作用下,太湖湖西区的风浪大于东部湖区;而受盛行于冬季的偏北风影响,太湖南部水域风浪要大于北部.同时,太湖风浪的时空分布特征是造成太湖水质参数、沉积物和水生植物空间分布差异的重要原因之一. 相似文献
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大型浅水湖泊太湖波浪特征及其对风场的敏感性分析 总被引：4，自引：2，他引：2
以空间均匀的实际风场为驱动,利用SWAN模式模拟了太湖波浪场,结果表明:SWAN模式能够较好的模拟太湖波浪的生成与传播,适用于大型浅水湖泊(太湖);同时分析了该风场驱动下下太湖风浪谱,波浪的绝对频率主要集中在0.45～1.0 Hz的中高频率段;风向与波向具有高度一致性.在同一风速下,太湖不同区域波浪成长稳定时间不同,湖心区稳定的谱峰频率在0.342～0.585 Hz之间,湾区及西山岛附近狭长水域稳定的谱峰频率在0.447～0.765 Hz之间;在同一区域,风速增大,波浪稳定时间减少,谱峰频率沿低频推移,在湖心区谱峰频率最小不低于0.340 Hz,湾区、西山岛附近狭长水域最小不低于0.447 Hz;风向的改变对湾区及西山岛附近狭长水域的波浪频谱形状影响较大. 相似文献
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采用原位观测平台,研究分析了太湖竺山湾风速、湖流流速、波高以及藻类水平漂移特征及其影响因素,结果表明日间藻类水平漂移速率呈锯齿式交替特征,日内藻类水平漂移速率变化幅度大;藻类水平漂移速率与风速之间呈显著线性正相关;当0.02 m < 有效波高 < 0.1 m时,藻类水平漂移速率与有效波高呈显著线性负相关,当有效波高 > 0.1 m时,波浪会显著改变藻类运动方式,破坏藻类表层聚集形态;湖流对藻类水平漂移速率无显著性影响;藻类水平漂移方向受湖流流向和风向的共同作用;藻类水平漂移速率与风速、波高、湖流流速间关系可用多元线性方程表达,且拟合度良好,可为藻类水华预测模型构建提供依据. 相似文献
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水动力条件下太湖透明度模拟研究 总被引：6，自引：0，他引：6
根据太湖实测资料分析得到了太湖悬浮物浓度和透明度之间呈现明显的反比关系, 归纳总结了以往研究成果中建立的太湖透明度与悬浮物浓度之间的关系, 说明可以通过模拟太湖悬浮物来反映太湖透明度的变化规律. 实测资料表明, 不同水深处的悬浮物浓度与风速的变化趋势大致相近, 风速越大, 悬浮物浓度越大. 太湖波浪、湖流与悬浮物浓度均呈现正相关关系, 悬浮物浓度随着波浪和湖流的增大而增大, 但波浪是影响底泥再悬浮的主要因素, 流速次之. 建立了太湖湖流、波浪和悬浮物耦合的数学模型, 在悬浮物模型中考虑了波浪和湖流的综合影响. 并将床面层附近底泥的起悬量和沉降量分开处理, 考虑了近底水流中湍流脉动的随机特性, 引入了底泥起悬条件. 模型清楚地反映出了悬浮物中的底泥颗粒与床面层内运动底泥及床面活动底泥发生相互交换过程中的两个方面. 模拟结果表明太湖悬浮物沿岸区域受湖流的影响较大, 湖心区域受波浪影响较大. 利用该模型, 模拟了太湖悬浮物和透明度的变化规律, 模拟结果被实测值较好验证, 说明所建立的模型是基本合理的, 可用来进行太湖透明度的模拟和预测. 相似文献
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风场对藻类在太湖中迁移影响的动力学研究 总被引：26，自引：10，他引：26
在Ｗｅｂｓｔｅｒ等人工作的基础上，以三维湖流为背景，考虑了波浪及藻类自身浮力的影响，建立了一个太湖梅梁湾三维藻类迁多模型，以研究在不同几场作用下藻类在湖泊中的迁移过程。模拟结果表明，不同风场对于藻类在湖泊中的水平及垂直分布影响很大，并且存在着一临界风速，其范围在２－３ｍ／ｓ之间，当几速小于临床风速时，水面可以拟看作水动力学光滑，没有波浪产生，在水表面藻类顺着风向迅速的向迎风岸的边漂移，形成藻类大量 相似文献
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通过用无量纲分析和线性回归方法对2002-2003年太湖4测点1000多组波浪资料的分析,给出了太湖不同时段风浪平均波高(H)与风区长度(F)、水深(d)、风速(v)6个关系模式.在此基础上,开展了模式的误差分析及与前人模式对比.结果表明,太湖北部不同区域风浪平均波高的计算应选用不同计算模式,但是可用如下形式表示:其中,a1-a8为和地形及水生植物覆盖度等相关的参数.误差分析结果显示:离岸距离大于1km区域的参数a1-a8的取值分别为0.217456、1、0.15、0.6、0.09、0.6、1.0、0.0052,模式估算平均波高的误差小于24％;近岸区参数a7大于1,a8取0,a4取值介于0.6-0.72,a5介于0.00131-0.00168,模式估算平均波高的误差较大,表明近岸区波浪还需进行进一步的观测研究. 相似文献
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以福建省平潭至长乐跨海大桥为工程背景,研究了多风向影响下的跨海大桥风致行车安全问题.建立了典型车辆在多风向侧风作用下发生侧滑以及侧倾的力学分析模型,确定了其在桥面行驶的安全风速.为表示不同规格风障的减风效果,借助于桥面风环境的风洞试验手段,获得了不同风向的风速折减系数.进一步,针对不同限速和不同路面工况的影响,研究了不... 相似文献
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下击暴流是雷暴天气产生的近地面短时强风,具有和大气边界层近地风显著不同的风场特征,其风荷载数值模拟方法也和常规风荷载模拟方法不同。在将下击暴流风速表达为时变的平均风速和调制的非平稳脉动风速之和的前提下,本文采用基于改进的OBV模型（Oseguera and Bowles／Vicroy（OBV））的方法来模拟平均风速,其平均风速直接由改进的OBV模型表达,而不同于已往研究中将平均风速表达为竖向风剖面与时间函数的乘积,并采用结合快速傅里叶变化的谐波叠加法来模拟调制的非平稳脉动风速。改进的OBV模型考虑了下击暴流的风暴中心移动和强度演化的影响,更准确地描述了下击暴流的实际物理过程。通过实例仿真,说明结果准确合理。 相似文献
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Study on the simulation of transparency of Lake Taihu under different hydrodynamic conditions 总被引：2，自引：0，他引：2
It was indicated in this study that there were negative relations between the concentrations of suspended solid (SS) and transparency according to the analysis of measured data of Lake Taihu. Their relations in pervious studies were reviewed, which showed that the changes of transparency in Lake Taihu could be reflected by simulating suspended solid concentration (SSC). Measured data showed that the changes of SSC with wind speed were similar at different water depths. SSC increased with the increasing of wind speed. Both wave and lake current of Lake Taihu had positive relations with SSC. However, wave was the main factor affecting sediment suspension, while flow took the second place. In this study, a numerical model coupling lake current, wave and SSC of Lake Taihu was developed. In the SS model, the combined effects of wave and current were included. The amounts of suspended and deposited sediments near the lake bed surface layer were treated separately. The stochastic characteristics of turbulent flow pulsation near lake beds were also considered, and the start-up conditions of sediment suspension were introduced to the model. The model elucidated the mutual exchange processes between sediment particles in SS and active sediments within and on the bed surface layer. Simulated results showed that lake current had relatively significant effects on the SSC at littoral areas of Lake Taihu, while SSC at the central area of the lake was mainly influenced by wave. The changes of transparency with SSC were simulated for Lake Taihu using this model. Calculated results were validated by measured data with good fitness, which indicated that the model is basically suitable for the simulation and prediction of transparency of Lake Taihu. 相似文献
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It was indicated in this study that there were negative relations between the concentrations of suspended solid (SS) and transparency according to the analysis of measured data of Lake Taihu. Their relations in pervious studies were reviewed, which showed that the changes of transparency in Lake Taihu could be reflected by simulating suspended solid concentration (SSC). Measured data showed that the changes of SSC with wind speed were similar at different water depths. SSC increased with the increasing of wind speed. Both wave and lake current of Lake Taihu had positive relations with SSC. However, wave was the main factor affecting sediment suspension, while flow took the second place. In this study, a numerical model coupling lake current, wave and SSC of Lake Taihu was developed. In the SS model, the combined effects of wave and current were included. The amounts of suspended and deposited sediments near the lake bed surface layer were treated separately. The stochastic characteristics of turbulent flow pulsation near lake beds were also considered, and the start-up conditions of sediment suspension were introduced to the model. The model elucidated the mutual exchange processes between sediment particles in SS and active sediments within and on the bed surface layer. Simulated results showed that lake current had relatively significant effects on the SSC at littoral areas of Lake Taihu, while SSC at the central area of the lake was mainly influenced by wave. The changes of transparency with SSC were simulated for Lake Taihu using this model. Calculated results were validated by measured data with good fitness, which indicated that the model is basically suitable for the simulation and prediction of transparency of Lake Taihu. 相似文献
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大气-水耦合模式下三维太湖湖流场研究 总被引：6，自引：1，他引：6
利用太湖区域的大气边界层三维数值模式和三维水动力学数值模式,采用气-水耦合方法,对太湖的风生流特征进行了深入研究。结果表明,太湖区域大气边界层风场具有明显的时空变化特征,与均匀定常风作用下的太湖流场相比,大气-水耦合模式下太湖流场变化较大,形成稳定湖流场所需的时间也较长。三维模式计算出的流速值明显比二维模式大(表层约大一倍,整层平均约大50％),且与实际观测值符合较好。故即使对于像太湖这样的浅水湖泊,三维水动力学模式的应用仍然是很必要的。模拟结果中还发现湖流的上下流矢有时出现非常大的切变,甚至达到了180°。由于浅水湖中仍存在两个边界层(水-气和水-土),故浅水湖中存在流矢的巨大切变是可能的。 相似文献
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Wave measurement and modeling in Chesapeake Bay 总被引：4，自引：0，他引：4
Three recently measured wind and wave data sets in the northern part of Chesapeake Bay (CB) are presented. Two of the three data sets were collected in late 1995. The third one was collected in July of 1998. The analyzed wind and wave data show that waves were dominated by locally generated, fetch limited young wind seas. Significant wave heights were highly correlated to the local driving wind speeds and the response time of the waves to the winds was about 1 h. We also tested two very different numerical wave models, Simulation of WAves Nearshore (SWAN) and Great Lakes Environmental Research Laboratory (GLERL), to hind-cast the wave conditions against the data sets. Time series model–data comparisons made using SWAN and GLERL showed that both models behaved well in response to a suddenly changing wind. In general, both SWAN and GLERL over-predicted significant wave height; SWAN over-predicted more than GLERL did. SWAN had a larger scatter index and a smaller correlation coefficient for wave height than GLERL had. In addition, both models slightly under-predicted the peak period with a fairly large scatter and low correlation coefficient. SWAN predicted mean wave direction better than GLERL did. Directional wave spectral comparisons between SWAN predictions and the data support these statistical comparisons. The GLERL model was much more computationally efficient for wind wave forecasts in CB. SWAN and GLERL predicted different wave height field distributions for the same winds in deeper water areas of the Bay where data were not available, however. These differences are as yet unresolved. 相似文献
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太湖不同湖区底泥悬浮沉降规律研究及内源释放量估算 总被引：5，自引：1，他引：4
太湖是一个大型浅水湖泊,湖湾、沿岸及湖心等区域受地形影响,湖流结构及水土界面水力要素均有显著差异.针对目前对不同湖区底泥再悬浮规律差异性研究的缺失,本研究选取了3个具有代表性的点采集太湖底泥,采用矩形水槽开展底泥再悬浮模拟实验,并结合太湖二维水量水质模型及太湖全年实测数据,建立了不同湖区底泥再悬浮通量与风速之间的定量关系;通过室内静沉降实验,得到了静沉降通量与风速的相关关系;最后将底泥再悬浮实验结果参数化应用于太湖二维水量水质模型中,并对底泥悬浮沉降过程进行分解和概化,估算太湖全年内源释放量.结果表明:太湖每日的内源释放量受风速影响显著,和风速变化趋势较为接近,太湖全年进入水体的净底泥量有47.81×104t,夏季最大,冬季次之;就营养物质释放量而言,COD约为2.06×104t、总氮约为1149.05 t、总磷约为564.35 t,其中秋季营养物质释放量最小,夏季最大. 相似文献
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基于高频次GOCI数据的太湖悬浮物浓度短期动态和驱动力分析 总被引：2，自引：0，他引：2
总悬浮物是水体中重要的光学敏感物质之一,很大程度上决定了水柱中光的吸收、散射和衰减,同时吸附营养盐、重金属和有毒有害物,对水体物质生物地球化学过程、沉积物埋藏动力和湖泊环境演化具有重要的意义.基于星地同步实验和静止水色成像仪GOCI(Geostationary Ocean Color Imager)构建了太湖悬浮物浓度估算模型,并分析了典型风浪过程中太湖悬浮物浓度短期动态变化过程.研究表明:对太湖水体悬浮物浓度较为敏感的波段为GOCI的第7波段(745nm)和第8波段(865 nm),悬浮物浓度与对应波段遥感反射率线性相关决定系数分别为0.72和0.55;基于GOCI第7波段的悬浮物浓度单波段遥感估算模型能较为准确地估算太湖的悬浮物浓度,模型相对均方根误差和平均绝对百分误差分别为28.3%和24.4%.通过研究典型风浪过程前后太湖悬浮物浓度变化发现其短期动态变化显著,风速、风向是悬浮物浓度短期动态变化的重要驱动因素,悬浮物浓度与风速呈正比,并随着风向扩散;高频连续GOCI影像结果显示悬浮物浓度短期动态变化对风浪扰动的响应有一定的滞后性,滞后时间为数小时到1天,悬浮物沉降与沉积物再悬浮的临界风速约为3.4 m/s. 相似文献