掺气减蚀段流场为水气两相流,掺气空腔后水气混掺剧烈,数值模拟难度大,尤其是临底掺气浓度,查阅的文献中计算结果普遍偏大。结合泄洪洞掺气设施对掺气水流进行数值模拟研究,通过二维流场模拟对不同的两相流模型和特征参数进行比较,总结出掺气水流的模拟方法。采用Eulerian模型对掺气水流进行三维全域流场模拟,对比分析水面线、通气量、掺气浓度等水力参数,计算结果与实测数据吻合较好,临底掺气浓度分布与实际情况相符,突破了掺气水流的模拟瓶颈,该模拟方法可为实际工程服务。

关键词：水力学； 掺气水流；数值模拟；掺气浓度；泄洪洞

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描述了浮摆式波能发电装置中浮体系统的收集原理,并对浮体系统的具体结构参数进行说明;在Workbench平台DesignModeler模块的基础上,对浮摆式波能发电装置中的浮体系统进行建模;对仿真过程中AQWA用到的基本方程、初始条件和需注意的事项进行了分析说明;并基于AQWA水动力学计算软件,对浮体的附加质量、辐射阻尼和RAO值进行计算,分析模拟了三种变化波况下浮体的运动响应情况,对浮箱的最大采集效率进行估算。仿真计算结果发现:1浮体的垂荡振幅大于浮箱的垂荡振幅,辐射阻尼随波浪频率的增大而增大,附加质量随波浪频率增大而缓慢减小;2周期和波高分别影响垂荡波形图的宽度和高度,周期较小时,应该注意锚链的疲劳断裂;3浮箱的最大采集效率为42.8%。

关键词：浮摆式波能发电装置；浮体系统；AQWA软件；数值仿真

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由于近岸斜向入射波浪演变、破碎等效应而形成的近岸波流场是近岸海域重要的环境水动力因素,对近海污染物的输运起着显著的影响。本文建立了曲线坐标系下相耦合的基于抛物型缓坡方程的波浪传播数值模型、近岸流数值模型及近岸波流场中的污染物输运数值模型,以近岸波流场为动力基础对不规则岸线地形下近岸污染物的输移扩散进行了数值模拟研究。应用上述联合数值模型对近岸沿岸流作用下的污染物输移扩散进行了数值模拟验证分析,数值模拟效果良好。进而将数值模型应用于Gourlay物理模型实验,对该地形近岸流作用下的污染物输运进行了数值模拟分析,污染物分布数值结果与作为其动力基础的近岸波流场表现出良好的一致性。

关键词：环境水力学；污染物输运；数值模拟；曲线坐标系 抛物型缓坡方程；近岸流

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针对常规水电机组振动故障诊断技术中易出现错判及诊断可靠性低等问题,提出了一种基于改进D-S证据理论的集成故障诊断方法。根据水电机组振动故障的频域信号,由模拟退火粒子群混合算法来处理证据理论的基本概率分配问题。再利用改进D-S理论来实现可信度分配的合理赋值,最后进行多信息的融合决策。实例表明,该方法可以在原始证据出现高度冲突以及相一致的情况下,都具有较高的诊断可信度,从而实现了对水电机组振动故障模式的有效识别。

关键词：水电工程；故障诊断；信息融合；改进D-S证据理论；水电机组

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The LRT system in Denver, Colorado, connects the downtown with neighborhoods to the North, but primarily stretches southwards, travelling in existing transportation corridors carrying freeways and a heavy rail system. Outside of the downtown areas, the siting of the LRT system alongside the rigid infrastructure that comprises the heavy rail system and the freeway systems severely inhibits pedestrian accessibility to the transit system. To help further understand how the level of accessibility varies across the system, a systematic pedestrian level-of-service index for each station within the system was created that takes into account the formal, as well as informal street networks. This inaccessibility is highly likely to limit the potential that this system may have to generate development near station located that is fully integrated with the LRT system. Primary data collected by surveying households across the metropolitan area revealed very little difference between car ownership rates and weekly VMT of survey respondents living within 12- mile of an LRT station and elsewhere in the metropolitan area. Differentiating between those station areas that were Park-and-Ride (that is, had a park-and-ride lot) versus Walk-and-Ride showed a more nuanced picture. Residents who live in Walk-and-Ride stations do have have lower VMT than those who live in Park-and-Ride station areas and those who do not live near an LRT station. This reinforces the fact that development needs to be more fully integrated with the LRT system in order to achieve some intended goals such as less dependence on automobiles.

关键词：公共交通;交通行业;可访问性;高速公路;政府政策

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A publication of recent energy statistics, this publication includes total energy production, consumption, and trade; energy prices; overviews of petroleum, natural gas, coal, electricity, nuclear energy, renewable energy, and international petroleum.

关键词：能源；生产；价格；煤炭；电力；核能源；石油；天然气；统计数据

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本报告从能源行业事件分析；竞争环境、竞争对手、行业数据等几个方面进行了分析评论。

关键词：行业事件分析；竞争环境；竞争对手；行业数据

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Alternative fuels have the potential to provide significant economic and environmental benefits to airports and their communities. These fuels can lead to improvements in local air quality emissions and reductions in life-cycle greenhouse gases. In addition, alternative fuels offer the possibility to diversify away from imported conventional petroleum-derived fuels and enhance energy security. Furthermore, alternative fuel distribution programs offer airports additional business opportunities to generate revenue through the operation of such facilities or leasing of land to third-party operators. Airports are natural nodes for multi-modal demand and are ideally situated to become distribution centers for a variety of alternative fuels for aircraft and surface transportation. Producers and marketers of alternative fuels can take advantage of this concentrated demand to strengthen their business case as they can cater to a wide spectrum of potential clients, including airlines, airports, and third-party operators such as rental car facilities, courtesy shuttles, taxis, buses, freight trucks, and other fleets that may operate nearby. This is especially the case for facilities that produce alternative jet fuel because, in addition to jet fuel, they also produce co-products such as green diesel, which can be used by some passenger and most cargo vehicles.

关键词：燃料;选择;空气质量;飞机;企业;柴油燃料;经济分析;排放

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评价了最新发布的TRMM 3B43V7降水数据在赣江流域19个水文站集水区域的精度,然后采用新构建的两参数月水量平衡模型—WBM-DP(Water Balance Model With Double Parameters)模拟了各水文站月径流过程,并与TRMM 3B43V6进行了比较。结果表明:就面雨量而言,在各集水区域,3B43V7相对比较稠密的地面雨量站网观测数据的系统误差幅度在11.0%以内,确定性系数不低于0.86。3B43V7对19个水文站月径流模拟的水量相对误差均值为-8.6%,确定性系数均值为0.84。与3B43V6相比,3B43V7的精度得到进一步提高,对多个水文站月径流的模拟效果改善明显。

关键词：水文学； TRMM 3B43V7；水量平衡模型；月径流过程模拟；赣江流域

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建立了适应于结构网格的复杂边界浅水流动有限体积数学模型。基本控制方程采用对自由水面相对高度在水平向和垂直项进行分裂后形成的守恒性的修正二维浅水方程,在结构网格上采用中心型格式离散基本控制方程,采用能够有效捕捉激波的近似黎曼求解器HLLC计算界面通量,并使用坡度限制器重构界面两侧变量,利用MUSCL-Hancock在时间维上积分,使时空精度提升到二阶;分别采用中心差分格式和全隐式方法处理底坡项和阻力项,保证了模型稳定性。提出了局部修正底高和水位的干湿边界处理方法和基于B样条曲线的复杂边界处理方法,很好地处理了急变水流变化引起的干湿单元网格的动态交替和复杂边界处水流特性正确表达。最后通过算例证明了模型性能较好,具有推广价值。

关键词：水力学；溃坝水流；结构网格；浅水方程；复杂边界

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