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Hydrography, currents and distribution of suspended matter during a dumping experiment in the western Baltic Sea at a site near Warnemünde 总被引:1,自引:1,他引:0
During a dumping experiment on 20/21 June 2001, an extensive data record was collected to understand the dynamical processes in the water column of the investigation area and to validate model results. Weak westerly winds with strongly changing cloud coverage characterized the meteorological situation. During the second day the wind calmed down and moved shortly to easterly directions. The water column was characterized by a strong vertical stratification with discontinuity layers in temperature and salinity in 12 and 16 m. The current regime was dominated by outflow at the water surface and inflow along the German coast, with strong current shearing in the dumping area. The suspended matter clouds could be identified by optical methods and ADCP (Acoustic Doppler Current Profiler) scattering intensity. During the experiment the suspended matter plumes were only visible at the surface up to 1 h after the dumping. The aerial photographs document that the particle clouds at the surface drifted to the west and, after approximately 40 min, they were only weakly visible. The fine material was concentrated in the discontinuity layer leading to substantially higher values of optical parameters and suspended matter concentration than measured in the surface clouds. Due to the vertical current shears the material was transported in the water column in different directions. At the first day the maximum of the suspended matter in the discontinuity layer was in the north-western corner and in the bottom layer in the northeast corner of the dumping area. Strong wind conditions after the dumping led to periodical resuspension processes. 相似文献
124.
Wave energy assessments in the Black Sea 总被引:1,自引:0,他引:1
Eugen Rusu 《Journal of Marine Science and Technology》2009,14(3):359-372
The present work aims to evaluate the wave energy resources in the Black Sea basin. The study is focused on the western part
of the sea, which is traditionally considered as being more energetic. In order to give a first perspective of the wave climate,
a medium-term wave analysis was carried out using in situ measured data. As a further step, a wave prediction system was implemented
for the Black Sea. This was based on the simulating waves near-shore model, which is used for both wave generation and near-shore
transformation. This methodology has the advantage that a single model covers the full scale of the modelling process. Various
tests were performed considering data measured at three different locations. Special attention was paid to the whitecapping
process, which is still widely considered to be the weak link in deep water wave modelling. Comparisons carried out against
measured data show that the wave prediction system generally provides reliable results, especially in terms of significant
wave heights and mean periods. By increasing the resolution in geographical space, the field distributions of wave energy
were analysed for both high and average wave conditions. The analysis and the wave prediction system developed are a prerequisite
for further investigations extended in time and with increased resolution in the near-shore direction. 相似文献
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随着经济的发展、综合国力增强,交通事业日新越益发展,桥梁建设取得了长足的进步,为我国的各项事业的发展提供了坚强的基础,但随之而来的桥梁病害问题也日益严重,针对上述情况,本文将对钢筋混凝土简支梁桥梁体的常见病害进行归纳和总结,并提出一定的维修措施,以便能够减轻同类病害的发生,为今后的公路事业发展提供参考依据. 相似文献
127.
车辆噪声与城市道路路面平整度关系的试验研究 总被引:4,自引:3,他引:4
主要研究了城市道路平整度可能对机动车辆噪声级产生的影响。采用IRI作为道路平整度的计量单位,并在上海的一些城市道路上组织了沥青路面和水泥路面两类试验。首先,在满足试验条件的道路上进行平整度的量测;其次,在试验道路的测点上采集车辆以特定速度驶过的最大噪声级。通过对试验数据的分析,发现车辆以相同速度行驶在平整度不同的城市道路上时,其噪声级是不同的,而且随着平整度指数的增加,机动车辆噪声级也呈上升趋势,因此城市道路平整度确实会对机动车辆噪声级产生影响。在20~50 km/h速度范围内,对于平整度相同的水泥路面和沥青路面,前者的车辆匀速行驶噪声要高于后者。 相似文献
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129.
轮轨滚动噪声激扰模型研究 总被引:5,自引:0,他引:5
为解决轮轨高频非线性接触问题和预测轮轨滚动噪声,需研究轮轨表面粗糙度的时域模型。在基于线性化理论的轮轨表面粗糙度频域表示方法的基础上,为满足轮轨非线性接触的要求,采用时频转换的方法建立轮轨表面粗糙度时域输入模型,并以Sato轮轨表面粗糙度谱为例,运用所建立的轮轨噪声预测模型及开发的轮轨噪声预测分析软件对轮轨滚动噪声辐射进行了仿真计算,将得到的轮轨滚动噪声频谱特征及其时域特点与工程实际监测结果进行对比分析,证明模型是可靠的。 相似文献
130.
在煤矸石隧道中出现塌方时,要通过地表注浆加固和隧道内长大管棚注浆,来达到内外兼治的目的;再配合超前小导管注浆,重新开挖隧道塌体,对隧道塌方进行综合治理,以保证施工及运营安全。文章结合吉林省某隧道处理塌方的工程实践,着重论述了不同岩体条件下的注浆技术及塌方体内大管棚安装技术,可为类似地质条件下的施工提供借鉴和参考。 相似文献