In this work,the flow surrounding the train was obtained using a detached eddy simulation(DES)for slipstream analysis.Two different streamlined nose lengths were investigated:a short nose(4 m)and a long nose(9 m).The ...In this work,the flow surrounding the train was obtained using a detached eddy simulation(DES)for slipstream analysis.Two different streamlined nose lengths were investigated:a short nose(4 m)and a long nose(9 m).The time-average slipstream velocity and the time-average slipstream pressure along the car bodies were compared and explained in detail.In addition to the time-averaged values,the _(max)imum velocities and the pressure peak-to-peak values around the two trains were analyzed.The result showed that the nose length affected the slipstream velocity along the entire train length at the lower and upper regions of the side of the train.However,no significant effect was recognized at the middle height of the train along its length,except in the nose region.Moreover,within the train’s side regions(y=2.0-2.5 m and z=2-4 m)and(y=2.5-3.5 m and z=0.2-0.7 m),the ratio of slipstream velocity U_(max) between the short and long nose trains was notably higher.This occurrence also manifested at the train’s upper section,specifically where y=0-2.5 m and z=4.2-5.0 m.Similarly,regarding the ratio of _(max)imum pressure peak-to-peak values Cp-p_(max),significant regions were observed at the train’s side(y=1.8-2.6 m and z=1-4 m)and above the train(y=0-2 m and z=3.9-4.8 m).展开更多
利用 23 a （1964—1986 年）的假潮资料，讨论了龙口港假潮的振幅、频率、周期和持续时间等；给出了导致假潮的各种天气形势和风场；分析了不同气象要素对假潮的贡献；探讨了大和特大振幅假潮的成因。分析结果表明：风场变化是导致龙...利用 23 a （1964—1986 年）的假潮资料，讨论了龙口港假潮的振幅、频率、周期和持续时间等；给出了导致假潮的各种天气形势和风场；分析了不同气象要素对假潮的贡献；探讨了大和特大振幅假潮的成因。分析结果表明：风场变化是导致龙口港假潮的直接原因；100 cm 左右和 >150 cm 的大和特大振幅假潮，是龙口港特殊地理环境、港湾及附近大范围海域骤猛的向港爆发性大风尤其强雷暴大风涌水在港内骤然积聚和海水惯性振荡的综合结果，该假潮具有较大危害性。展开更多
To disclose the grain crushing effects on the weathered granular soil rheological behavior,a series of rheological tests (odometer compression and triaxial shearing) were carried out.At the same time,the sieving analy...To disclose the grain crushing effects on the weathered granular soil rheological behavior,a series of rheological tests (odometer compression and triaxial shearing) were carried out.At the same time,the sieving analysis tests of these specimens were also executed before and after tests,and the grain crushing degree,Br and n5,were collectively adopted to estimate the grain crushing.The grain crushing degree depends on the stress path,stress level,and load time,especially,the longer load time and more intensive gradient shearing path will increase the grain crushing quantity.The Hardin crushing degrees Br are 0.191,0.118 and 0.085 in the ordinary compression,rheological compression and triaxial rheological shearing,respectively;The grain crushing degrees n5 are 1.9,1.4 and 1.32,respectively.The strain softening phase indicates the grain crushing and diffusive collapse,and the strain hardening phase indicates the rearrangement of these crushed grains and formation of new bearing soil skeleton.The rheological deformation of granular soil can be attributed to the coarse grain crushing and the filling external porosity with crushed fragments.展开更多
基金Project(52202426)supported by the National Natural Science Foundation of ChinaProjects(15205723,15226424)supported by the Research Grants Council of the Hong Kong Special Administrative Region(SAR),China+1 种基金Project(K2021J041)supported by the Technology Research and Development Program of China RailwayProject(1-BD23)supported by The Hong Kong Polytechnic University,China。
文摘In this work,the flow surrounding the train was obtained using a detached eddy simulation(DES)for slipstream analysis.Two different streamlined nose lengths were investigated:a short nose(4 m)and a long nose(9 m).The time-average slipstream velocity and the time-average slipstream pressure along the car bodies were compared and explained in detail.In addition to the time-averaged values,the _(max)imum velocities and the pressure peak-to-peak values around the two trains were analyzed.The result showed that the nose length affected the slipstream velocity along the entire train length at the lower and upper regions of the side of the train.However,no significant effect was recognized at the middle height of the train along its length,except in the nose region.Moreover,within the train’s side regions(y=2.0-2.5 m and z=2-4 m)and(y=2.5-3.5 m and z=0.2-0.7 m),the ratio of slipstream velocity U_(max) between the short and long nose trains was notably higher.This occurrence also manifested at the train’s upper section,specifically where y=0-2.5 m and z=4.2-5.0 m.Similarly,regarding the ratio of _(max)imum pressure peak-to-peak values Cp-p_(max),significant regions were observed at the train’s side(y=1.8-2.6 m and z=1-4 m)and above the train(y=0-2 m and z=3.9-4.8 m).
文摘利用 23 a （1964—1986 年）的假潮资料，讨论了龙口港假潮的振幅、频率、周期和持续时间等；给出了导致假潮的各种天气形势和风场；分析了不同气象要素对假潮的贡献；探讨了大和特大振幅假潮的成因。分析结果表明：风场变化是导致龙口港假潮的直接原因；100 cm 左右和 >150 cm 的大和特大振幅假潮，是龙口港特殊地理环境、港湾及附近大范围海域骤猛的向港爆发性大风尤其强雷暴大风涌水在港内骤然积聚和海水惯性振荡的综合结果，该假潮具有较大危害性。
基金Project(50908233) supported by the National Natural Science Foundation of ChinaProject(200413) supported by Communication Science and Technology Fund of Hunan Province,China
文摘To disclose the grain crushing effects on the weathered granular soil rheological behavior,a series of rheological tests (odometer compression and triaxial shearing) were carried out.At the same time,the sieving analysis tests of these specimens were also executed before and after tests,and the grain crushing degree,Br and n5,were collectively adopted to estimate the grain crushing.The grain crushing degree depends on the stress path,stress level,and load time,especially,the longer load time and more intensive gradient shearing path will increase the grain crushing quantity.The Hardin crushing degrees Br are 0.191,0.118 and 0.085 in the ordinary compression,rheological compression and triaxial rheological shearing,respectively;The grain crushing degrees n5 are 1.9,1.4 and 1.32,respectively.The strain softening phase indicates the grain crushing and diffusive collapse,and the strain hardening phase indicates the rearrangement of these crushed grains and formation of new bearing soil skeleton.The rheological deformation of granular soil can be attributed to the coarse grain crushing and the filling external porosity with crushed fragments.
