Results 51 to 60 of about 7,370 (165)
Shuitu Baochi Xuebao, 2018 通过室内定床冲刷试验，选用砂布床面模拟土壤下垫面，选用砂布+塑料半球体（直径为40 mm）床面模拟大粗糙单元下垫面，在较大流量（2.81~84.43 L/min）、坡度（2°~10°）范围内，系统研究了大粗糙单元对坡面流水动力学特性的影响。结果表明：（1）大粗糙单元床面的平均流速、平均水深和弗劳德数与流量之间均呈幂函数正相关关系；平均流速和弗劳德数与坡度之间均呈幂函数正相关关系，而平均水深与坡度之间呈幂函数负相关关系；阻力系数随雷诺数的增大而逐渐减小。（2）大粗糙单元增加了坡面流阻力，延缓了坡面流流速 ...
柳晓娜 +6 more
doaj
Analysis and Evaluation of Two-dimensional Hypersonic Inlet System Drag [PDF]
, 2015 进气道作为超燃冲压发动机的主要部件，其阻力特性对进气道优化选型、气动减阻、一体化设计等方面都具有重要影响。在高超声速试验中，阻力的直接测量相当困难，测量误差可达到50%以上，因此有必要采用间接方法来研究进气道的阻力特性。目前，学者们采用的阻力估算方法或多或少都存在一些缺陷，无法快速应用于高超声速进气道内部阻力的工程估算。 本文提出一种快速估算进气道阻力的方法，从进气道内控制体的动量定理出发，推导出进气道阻力特性的工程估算公式；重点研究了估算公式的数据处理形式，并分别用理论分析 ...
安平
core
Analysis of drag reduction characteristics of a high-speed monohull ship interceptor in shallow water [PDF]
ObjectivesThis study seeks to explore the influence of water depth on the drag reduction effect and optimal drag reduction height of an interceptor.
Anyang QIN +4 more
core +1 more source
World Medical &Health Policy, Volume 17, Issue 1, Page 129-148, March 2025.Abstract Patients with kidney failure need dialysis or a kidney transplant to survive. Living donor kidney transplantation (LDKT) is the best therapeutic option, yet global rates of LDKT have minimally increased, and there are disparities in access. The need for a systems approach to improvement has been highlighted.
Anna Horton +7 more
wiley +1 more source
Prediction of pre‐eclampsia using maternal hemodynamic parameters at 12 + 0 to 15 + 6 weeks
Ultrasound in Obstetrics &Gynecology, Volume 65, Issue 2, Page 173-182, February 2025.ABSTRACT Objectives To compare the maternal hemodynamic profile at 12 + 0 to 15 + 6 weeks' gestation in women who subsequently developed pre‐eclampsia (PE) and those who did not, and to assess the screening performance of maternal hemodynamic parameters for PE in combination with the Fetal Medicine Foundation (FMF) triple test, including maternal ...
X. Wang +9 more
wiley +1 more source
Shuitu Baochi Xuebao, 2001 利用供沙土槽和试验土槽的双土槽径流小区 ,定量研究了在不同降雨强度下上方来水来沙对陡坡地细沟侵蚀产沙过程和细沟水流水力学参数的影响及其细沟水流水力学特征参数与细沟侵蚀产沙量的关系。结果表明 :坡面细沟侵蚀过程以侵蚀—搬运过程为主 ,坡上方来沙不仅被径流全部搬运 ,且上方来水在坡下方引起了另外的侵蚀产沙量 ,其值随上方来水含沙量的减少和降雨强度的增加而增大。上方来水的汇入或降雨强度的增大可使细沟水流流态由层流转化为紊流。上方来水对细沟水流水力学参数 (流速、水力半径、雷诺数、弗劳德数和阻力系数 ...
肖培青 郑粉莉 等
doaj
Numerical Simulation on Aerodynamic of Ground Effect Vehicle's Wing [PDF]
, 2012 选取nACA5312翼型,利用fluEnT软件,采用有限体积法,求解定常可压缩流动的质量加权平均n-S方程和标准k-ε湍流模型,数值模拟地效飞行器在不同高度、速度及飞行迎角下的飞行状态。对比无界流场,研究了在地效作用下,气动特性与迎角 ...
吴榕, 梁峰
core
Resistance characteristics of gas-liquid two-phase flow in stick venturi scrubbers [PDF]
, 2017 In order to grasp the resistance characteristics of gas-liquid two-phase flow in stick venturi scrubbers, based on the multiphase flow theory, a three-dimensional CFD model was established.
BU Ying-yong +4 more
core +1 more source
Integrative Conservation, Volume 3, Issue 4, Page 294-311, December 2024.Freshwater biodiversity in China is threatened by multiple anthropogenic factors, and while there are some reasons to suppose it may be possible to bend the curve of biodiversity loss, the variety of threats and their likely interactions with ongoing climate change provide little basis for optimism. For example, the historic overexploitation of Yangtze
David Dudgeon
wiley +1 more source
Shuitu Baochi Xuebao, 2002 通过不同坡度、不同流量的组合放水冲刷试验 ,对坡面细沟侵蚀发生过程中的坡面流水动力学特性进行了研究。结果表明 ,在试验的坡度和流量范围内 ,坡面流的雷诺数变化于 36 2～ 4 2 84之间 ,并且其变化有随冲刷历时和流量的增大而增大的趋势。而坡面流弗劳德数在整个试验过程中均大于 1,属于急流范围。坡面流阻力系数的大小与水流雷诺数有关 ,但其变化趋势受坡度的影响。在坡度较缓时 ,阻力系数随雷诺数的增大而减小 ;在坡度较大时 ,阻力系数随雷诺数的增大而增大。在径流冲刷侵蚀过程中 ,径流流速并非一恒定值 ...
丁文峰 李占斌 等
doaj +2 more sources