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车用发动机 1988年第3期 38-41页

作者：强国芳中船总七院七○三研究所

本文从三个方面介绍了我所从英国引进的大功率高速水力测功器。首先说明设备引进的过程,其次介绍HS790测功器的主要性能及结构和系统的特点,最后提出对今后我国有关发展工作的建议和意见。

关键词：水力测功器 froude HS790

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张力腿平台内孤立波载荷及其理论模型

上海交通大学学报 2013年第10期47卷 1494-1502页

作者：黄文昊尤云祥王竟宇胡天群上海交通大学海洋工程国家重点实验室上海200240

在大型重力式密度分层水槽中,对内孤立波作用下张力腿平台的载荷特性开展了系列实验.基于两层流体内孤立波KdV(Korteweg-de Vries)、eKdV(extended KdV)和MCC(MiyataChoi-Camassa)理论,建立了张力腿平台内孤立波载荷的理论模型,给出了... 详细信息

在大型重力式密度分层水槽中,对内孤立波作用下张力腿平台的载荷特性开展了系列实验.基于两层流体内孤立波KdV(Korteweg-de Vries)、eKdV(extended KdV)和MCC(MiyataChoi-Camassa)理论,建立了张力腿平台内孤立波载荷的理论模型,给出了该理论模型中三类内孤立波理论的适用性条件.研究表明,张力腿平台的内孤立波水平载荷包括立柱与沉箱部分的拖曳力和惯性力,可由Morison公式进行计算,而其竖向载荷主要为竖向froude-Krylov力,可以通过内孤立波诱导动压力在立柱底部及沉箱上下湿表面进行积分计算.系列实验结果表明,在Morison公式中的拖曳力系数与内孤立波诱导速度场的雷诺数之间为指数函数关系,惯性力系数与KC(Keulegan-Carpenter)数之间为幂函数关系,而且基于所建立理论模型获得的张力腿平台水平力、竖向力及其力矩的计算结果与系列实验结果吻合.本项研究在系列实验基础上,为海洋工程张力腿平台的内孤立波载荷预报提供了一个实用的理论计算模型.

关键词：张力腿平台内孤立波两层流体 Morison公式 froude Krylov力

Phenomenon of the sediment deposition in a hydraulic jump region of open channels

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Journal of Mountain Science 2022年第7期19卷 1874-1885页

作者： XU Wei-lin WANG Guo-guang FU Shi-hao WEI Wang-ru State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China

The hydraulic jump is a typical sudden change for mountain river areas.The effects of local hydraulic jumps on the particle transport capacity decrease and local flow resistance increase cannot be ignored as the sediment deposition disaster can amplify the flash flood disaster.The present research investigates the influences of a hydraulic jump on the individual particle movement and sediment deposition in a laboratory flume.The overall processes of a single particle movement are captured by a high-speed camera.The distribution of sediment deposition along the hydraulic jump is obtained statistically.The results show that both the particle size and the ratio of the upstream and downstream froude numbers affect the particle motion process.A single particle coming from upstream gradually decelerates and finally stops at the hydraulic jump section because of hydraulic jump resistance.The particle acceleration first increases and then decreases during the time-domain process,and the attenuation trends are fast with the increase of ratio of upstream and downstream of froude numbers.The increase of the maximum acceleration with sediment flows follows a linear trend approximately,which indicates that the kinetic features of the single sand particle are determined by the coupling effects of the hydraulic jump resistance and the sand dynamic properties.With the increase of sediment rate and sand particle size,the resistance effect of hydraulic jump on sediment deposition rate along the flow direction gets strong and the sediment deposition area is mainly located upstream of the hydraulic jump region.The present study shows that the possible sediment supply upstream must be obtained for identifying the disaster risk combined with the local hydraulic jump conditions.Further researches about the detailed critical condition deduced from the relationship between the water flow and sediment deposition are required to confirm and extrapolate present results to other applications.

关键词： Ratio of upstream and downstream froude

Experimental Study of Tunnel Fire with Natural Ventilation

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湖南大学学报（自然科学版） 2009年第S1期36卷 23-25页

作者： YUAN Zhong-yuan,LEI Bo,CHEN Peng-yun(School of Mechanical Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China) School of Mechanical Engineering Southwest Jiaotong University Chengdu 610031 China

The 1/15 reduced-scale experiments using froude scaling were designed to study the effect on the smoke control efficiency for subway tunnel fires with natural ventilation mode.The propane gas fires with heat release rate 11.48 kW was used,which corresponds to the heat release rate 10 MW in the full-scale tunnel.The temperature distributions under the ceiling were measured by K-type thermocouples to investigate smoke movement,and the velocity of smoke in shafts was measured by hot-wire anemometer to obtain the smoke extract amount of ventilation shafts.The results show that the smoke temperature under the ceiling varies with the longitudinal different distance from fire source.The results also show that the smoke temperature distributions and the smoke control efficiency in tunnel vary with the space between ventilation shafts and vary with the area and the height of ventilation shaft.

关键词： natural ventilation mode metro tunnel fire reduced-scale experiments froude scaling

二维流入线汇分层流的froude数的权限值

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苏州大学学报(自然科学版) 1986年第4期 380-387页

作者：黄玲琍

本文从二维、无粘、不可压缩分层流的基本方程及其解出发,给出它们的本征值条件,并由该条件得出流入线汇的分层流的重要信息froude数F1的值（F1）>0.318。

关键词：分层流 froude 线汇二维流汇点

水面上低froude数二维物体引起的自由表面波与波阻

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中国科学(A辑数学物理学天文学技术科学) 1986年第3期 293-300页

作者：陈嗣熊中国科学院力学研究所北京

本文用广义WKB渐近展开,求得了波势函数的解析表达式。考虑到“朴实”渐近展开式在物体后缘点的奇异性,在该展开式中仅保留了零级近似项与一级近似项。波势函数的近似阶数和振幅中包含的未定常数因子,直接由物体表面边界条件与由“朴实... 详细信息

本文用广义WKB渐近展开,求得了波势函数的解析表达式。考虑到“朴实”渐近展开式在物体后缘点的奇异性,在该展开式中仅保留了零级近似项与一级近似项。波势函数的近似阶数和振幅中包含的未定常数因子,直接由物体表面边界条件与由“朴实”渐近展开式的一级近似项所满足的非齐次物体表面边界条件所确定。

关键词：渐近展开自由表面波一级近似展开(数学) 二维物体常数因子 froude 波阻气动阻力

Numerical Prediction of Total Resistance Using Full Similarity Technique

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China Ocean Engineering 2019年第4期33卷 493-502页

作者： Savas SEZEN Ferdi CAKICI Department of Naval Architecture and Marine Engineering Yildiz Technical University

Model tests are often conducted by researchers in a real or a numerical towing tank to calculate residuary resistance of a ship with the aid of froude similarity. Common ITTC-1957 formula is usually employed to calculate frictional resistance. As computer technologies develop over time, CFD tools are used for calculating total resistance of a ship at full scale without establishing any dynamic similarities. In this paper, both froude and Reynolds similarities are numerically implemented to four different model scales by using virtual fluids. The total resistance at different Fr numbers calculated by the numerical study is validated against the experimental data of DTMB 5512 (L=3.048 m) model hull. The results show that establishing froude and Reynolds similarities together in numerical simulation is possible in principle. To determine whether it has advantages for prediction of full-scale ship total resistance by employing this method, it is also examined the model scale with the same number of elements and Reynolds number of the full-scale ship. Results show that numerical calculation of total resistance for a full-scale ship in a model scale by defining virtual fluids has only slight advantages on the prediction of residuary resistance. Additionally, no advantage in the calculation of frictional resistance is observed.

关键词： total resistance froude and Reynolds similarities DTMB 5512 CFD

Dust as a Potential Tracer for the Flow over Different Topographical Shapes Employing MODIS-Terra Observations

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International Journal of Geosciences 2018年第7期9卷 428-434页

作者： Joseph Barkan Pinhas Alpert Dept. Geophysics School of Geosciences Tel Aviv University Tel Aviv Israel

The hypothesis, that the magnitude of the froude number can represent the flow type around an obstacle was examined at several different topographical shapes in dust-laden environments. It was found that in most cases this hypothesis was true. Average of 16 May months AOT data extracted from the MODIS Terra satellite has shown that in case of froude number less than one, the AOT isolines tend to follow the topographical contours of the mountain peak (the obstacle) along with a minimum AOT near the peak.

关键词： froude Number Dust MODIS Topographical Obstacles

Determining Critical Submergence in Tanks by Means of Reynolds &Weber Numbers

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World Journal of Engineering and Technology 2014年第3期2卷 222-233页

作者： Carlos Julián Gavilán Moreno Cofrentes NPP Technical Services Iberdrola Generacion Nuclear Cofrentes Spain

Critical submergence in pumping systems can be determined using a number of calculations, all of which result from heterogeneous geometries based on water. The most widely spread critical submergence formula is that of the Hydraulic Institute. A study, carried out in Germany, looked at eight different formulations used to calculate critical submergence, comparing their results with those of a hydraulic model test. The conclusion is that the simplest models, overestimate the critical submergence. Similarly, a study of submergence in water intake structures concluded that predicted values were much higher than real values. A detailed analysis has been done to detect the origin of the off-set between the measured submergence and the calculated value. The main aspects selected from the analysis were the fluid properties involved in the surface deformation and the dynamic behavior outlet flow, so two a-dimensional numbers have been selected, Weber and Reynolds. To build an equation, to calculate the critical submergence, based on the mentioned a-dimensional numbers, a mixed technique (numerical and testing) has been used. The first step was driving a test in a hydraulic model to verify the critical submergence level. Then, a numerical model was built to simulate the same phenomenon and calibrate it, to be used in the future. After that, the second step is to simulate and calculate the critical submergence with other boundary condition (fluid, flow rate, pipe diameter). Once the critical submergence is calculated, a non-linear least squared approach has been developed to build the equation to calculate the critical submergence based on the Reynolds and Weber number. The numerical method used in this paper is a finite element model with a fluid volume scheme, used normally in the fluid simulation activities.

关键词： Submergence froude Reynolds Weber Cavitation

Dust as a Potential Tracer for the Flow over Topography

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International Journal of Geosciences 2015年第1期6卷 42-50页

作者： Pinhas Alpert Joseph Barkan Department of Geosciences Tel-Aviv University Tel-Aviv Israel

The distribution of mineral dust around topographical obstacles is examined, employing the dimensionless froude number that describes different flow regimes in a fluid. Flow around a peak with a near-circular shape in a dusty environment like the Sahara and the Sahel was examined in order to investigate the distribution of the dust around the obstacle. The Total Ozone Mapping Spectrometer Aerosol Index (TOMS-AI) daily Aerosol Index, the u and v wind components and the temperature, were used for the period 1979-1992,?i.e. 14 years. It is found by the AI data that the shape of the dust distribution around the circular peak is in good agreement with the shape of the peak itself. Additionally good correlation exists between the vertical distribution of the dust above the peak and the froude Number in its vicinity. This method allows for the first time the investigation of the flow above and around topographical obstacles in different flow conditions in the open space employing dust as the flow tracer.

关键词： Dust Sahara froude Number TOMS Topographic Flow