Model study is an efficient method for optimizing the siructure of the mould and the submerged entry nozzle (SEN). Based on the similarity criteria, a full-scale water model has been established in accordance with the...Model study is an efficient method for optimizing the siructure of the mould and the submerged entry nozzle (SEN). Based on the similarity criteria, a full-scale water model has been established in accordance with the mould of thin-slab caster of the CSP (Compact Strip Production) operation. The effects of SEN structure including outlet area, outflow angle, nozzle width, thick-ness and immersion depth have been studied under high speed casting by measuring the amplitude and the impetus of top waves. By the orthogonal experiment design, not only the influence of the faCtors was estimated, but also the optimum work condition was judged. The rules of the fluid flow phenomena were summarized. The principle for choosing a reasonable structure of SEN was discussed.展开更多
The behavior of bubbles is observed with high-speed digital camera in water-model. It is found that each bubble has three processes: bubble formation, bubble coalescence and bubble division. Bubble shape is spherical ...The behavior of bubbles is observed with high-speed digital camera in water-model. It is found that each bubble has three processes: bubble formation, bubble coalescence and bubble division. Bubble shape is spherical firstly, then elliptical and spherical crown after coalescence, and spherical again after division. These phenomena are explained theoretically. And the bubble size is defined newly. The so-defined bubble size is measured through digital camera and LECO graphical analyzer. And the measured results are compared with those in literatures.展开更多
为支撑数字孪生流域建设与智慧水利发展,针对当前水文模型物理机制薄弱、功能单一、适应性不足及多模型松散耦合效率低等问题,本研究基于中国水利水电科学研究院自主研发的模型体系,研发了集成气象预报-流域产汇流-洪水预报-水库调度全...为支撑数字孪生流域建设与智慧水利发展,针对当前水文模型物理机制薄弱、功能单一、适应性不足及多模型松散耦合效率低等问题,本研究基于中国水利水电科学研究院自主研发的模型体系,研发了集成气象预报-流域产汇流-洪水预报-水库调度全链条、通用化的流域产汇流及洪水预报模型软件平台(Runoff Yield and Concen⁃tration in Watersheds and Flood Forecast Model,Sky-RyCF)。该软件以“自然-社会”二元水循环理论为主线,通过标准化接口深度融合了数值气象预报、分布式产汇流、时空变源产流、一二维水动力洪水演进、社会水循环及多目标调度等核心模块,构建了支持多模型耦合集成与可视化建模的一体化平台。应用结果表明:在永定河“23·7”特大洪水复盘模拟中,卢沟桥洪峰预报值4540 m^(3)/s(实测4650 m^(3)/s),泛区淹没面积模拟误差≤2.0%;在松花江流域水资源评估中,主要水文站月径流模拟Nash效率系数均大于0.7,定量揭示了水资源演变规律。该模型具有物理机制强、功能完备、智能通用等特点,实现了水循环多过程的精细化模拟与业务化应用,为水利“四预”(预报、预警、预演、预案)工作和智慧水利业务提供了核心技术支撑。展开更多
研究旨在探究振荡水柱(oscillating water column,简称OWC)防波堤前墙的受力特性。通过物理模型试验,利用狭缝开口模拟冲击式空气透平,测量前墙两侧的波浪压强和振荡水柱气室内气体压强,从而在计算前墙水平波致总力时计及波压力和气压...研究旨在探究振荡水柱(oscillating water column,简称OWC)防波堤前墙的受力特性。通过物理模型试验,利用狭缝开口模拟冲击式空气透平,测量前墙两侧的波浪压强和振荡水柱气室内气体压强,从而在计算前墙水平波致总力时计及波压力和气压力。研究结果表明,气室宽度比和狭缝开口率是影响波浪压强和气体压强的关键参数,其主要影响表现为:改变前墙两侧波浪压强的幅值,改变前墙两侧高波压区域的垂向宽度以及改变气压振荡的剧烈程度。在不同的气室结构参数和波浪参数组合下,前墙的最大水平波致力分布呈现两个高波力区域,时域分析结果表明,这两个区域的前墙水平波致力中波压分力与气压分力的峰值幅值和相位组合存在差异。文中特别强调气体压强在前墙水平波致力中的重要作用,受其主要影响,狭缝开口率小于1.50%的OWC防波堤前墙在B/L=0.15附近波浪作用下出现较大波致力。为确保OWC防波堤结构安全,设计时应根据海域波浪特征调整气室结构,避免或减少在前墙表面形成高波力区域。展开更多
现有GNSS水汽层析研究主要聚焦于如何提升卫星观测数据利用率,但在卫星信号数据优选方面研究较少,导致穿过同一组网格集的层析观测方程线性近似且方程系数矩阵列向量元素多数为零,水汽层析模型病态严重。针对该现状,本文提出一种GNSS卫...现有GNSS水汽层析研究主要聚焦于如何提升卫星观测数据利用率,但在卫星信号数据优选方面研究较少,导致穿过同一组网格集的层析观测方程线性近似且方程系数矩阵列向量元素多数为零,水汽层析模型病态严重。针对该现状,本文提出一种GNSS卫星信号自适应优选的水汽层析方法,解决层析模型设计矩阵零元素较多和层析模型病态的难题。该方法基于网格覆盖率最大原则确定层析区域水平网格划分,并发展联合卫星高度角与方位角阈值的卫星信号自适应优选方法,克服水汽层析模型观测方程线性近似的难题。本文选取香港地区2013年5月2日—2013年5月7日共6 d 12个GNSS测站及1个无线电探空站数据为例进行试验。与现有方法相比,本文方法能在降低卫星信号利用率的同时保证网格覆盖率,克服相似卫星信号造成层析模型设计矩阵病态的现状。以无线电探空数据为真值,发现本文方法反演水汽密度廓线的平均RMS、MAE和Bias分别为1.03、0.80和0.13 g/m^(3),优于传统方法的1.25、0.97和0.10 g/m^(3),其RMS改善率为20.78%;此外,本文方法在模型解算效率方面也优于传统方法,其模型计算效率平均提升9.51%。展开更多
文摘Model study is an efficient method for optimizing the siructure of the mould and the submerged entry nozzle (SEN). Based on the similarity criteria, a full-scale water model has been established in accordance with the mould of thin-slab caster of the CSP (Compact Strip Production) operation. The effects of SEN structure including outlet area, outflow angle, nozzle width, thick-ness and immersion depth have been studied under high speed casting by measuring the amplitude and the impetus of top waves. By the orthogonal experiment design, not only the influence of the faCtors was estimated, but also the optimum work condition was judged. The rules of the fluid flow phenomena were summarized. The principle for choosing a reasonable structure of SEN was discussed.
文摘The behavior of bubbles is observed with high-speed digital camera in water-model. It is found that each bubble has three processes: bubble formation, bubble coalescence and bubble division. Bubble shape is spherical firstly, then elliptical and spherical crown after coalescence, and spherical again after division. These phenomena are explained theoretically. And the bubble size is defined newly. The so-defined bubble size is measured through digital camera and LECO graphical analyzer. And the measured results are compared with those in literatures.
文摘为支撑数字孪生流域建设与智慧水利发展,针对当前水文模型物理机制薄弱、功能单一、适应性不足及多模型松散耦合效率低等问题,本研究基于中国水利水电科学研究院自主研发的模型体系,研发了集成气象预报-流域产汇流-洪水预报-水库调度全链条、通用化的流域产汇流及洪水预报模型软件平台(Runoff Yield and Concen⁃tration in Watersheds and Flood Forecast Model,Sky-RyCF)。该软件以“自然-社会”二元水循环理论为主线,通过标准化接口深度融合了数值气象预报、分布式产汇流、时空变源产流、一二维水动力洪水演进、社会水循环及多目标调度等核心模块,构建了支持多模型耦合集成与可视化建模的一体化平台。应用结果表明:在永定河“23·7”特大洪水复盘模拟中,卢沟桥洪峰预报值4540 m^(3)/s(实测4650 m^(3)/s),泛区淹没面积模拟误差≤2.0%;在松花江流域水资源评估中,主要水文站月径流模拟Nash效率系数均大于0.7,定量揭示了水资源演变规律。该模型具有物理机制强、功能完备、智能通用等特点,实现了水循环多过程的精细化模拟与业务化应用,为水利“四预”(预报、预警、预演、预案)工作和智慧水利业务提供了核心技术支撑。
文摘研究旨在探究振荡水柱(oscillating water column,简称OWC)防波堤前墙的受力特性。通过物理模型试验,利用狭缝开口模拟冲击式空气透平,测量前墙两侧的波浪压强和振荡水柱气室内气体压强,从而在计算前墙水平波致总力时计及波压力和气压力。研究结果表明,气室宽度比和狭缝开口率是影响波浪压强和气体压强的关键参数,其主要影响表现为:改变前墙两侧波浪压强的幅值,改变前墙两侧高波压区域的垂向宽度以及改变气压振荡的剧烈程度。在不同的气室结构参数和波浪参数组合下,前墙的最大水平波致力分布呈现两个高波力区域,时域分析结果表明,这两个区域的前墙水平波致力中波压分力与气压分力的峰值幅值和相位组合存在差异。文中特别强调气体压强在前墙水平波致力中的重要作用,受其主要影响,狭缝开口率小于1.50%的OWC防波堤前墙在B/L=0.15附近波浪作用下出现较大波致力。为确保OWC防波堤结构安全,设计时应根据海域波浪特征调整气室结构,避免或减少在前墙表面形成高波力区域。
文摘现有GNSS水汽层析研究主要聚焦于如何提升卫星观测数据利用率,但在卫星信号数据优选方面研究较少,导致穿过同一组网格集的层析观测方程线性近似且方程系数矩阵列向量元素多数为零,水汽层析模型病态严重。针对该现状,本文提出一种GNSS卫星信号自适应优选的水汽层析方法,解决层析模型设计矩阵零元素较多和层析模型病态的难题。该方法基于网格覆盖率最大原则确定层析区域水平网格划分,并发展联合卫星高度角与方位角阈值的卫星信号自适应优选方法,克服水汽层析模型观测方程线性近似的难题。本文选取香港地区2013年5月2日—2013年5月7日共6 d 12个GNSS测站及1个无线电探空站数据为例进行试验。与现有方法相比,本文方法能在降低卫星信号利用率的同时保证网格覆盖率,克服相似卫星信号造成层析模型设计矩阵病态的现状。以无线电探空数据为真值,发现本文方法反演水汽密度廓线的平均RMS、MAE和Bias分别为1.03、0.80和0.13 g/m^(3),优于传统方法的1.25、0.97和0.10 g/m^(3),其RMS改善率为20.78%;此外,本文方法在模型解算效率方面也优于传统方法,其模型计算效率平均提升9.51%。
