The effects of rigid vegetation on the turbulence characteristics were experimentally studied in the interior water flume. An ADV was used to determine the three dimensional turbulent velocities in clear water flow wi...The effects of rigid vegetation on the turbulence characteristics were experimentally studied in the interior water flume. An ADV was used to determine the three dimensional turbulent velocities in clear water flow without vegetation, sediment-laden flow without vegetation, sediment-laden flow with submerged vegetation and sediment-laden flow with non-submerged vegetation. By experimental and theoretical analysis, the effects of rigid vegetation on the distribution of averaged velocities, turbulence intensities and Reynolds stress were summarized. In sediment-laden flow with submerged vegetation, the averaged stream wise velocities above the top of vegetation fit well with the log distribution low. The three-dimensional turbulence intensities increase from the bottom until they reach the maximum at the top of the vegetation. The method to calculate the shear velocity with the maximum of the Reynolds stress is recommended. In sediment-laden flow with non-submerged vegetation, the turbulence problems cannot be explained by theory of bed shear flow. The average velocities, turbulence intensities and Reynolds stress approximate uniformly distributed along vertical direction.展开更多
文章通过对河西地区最近150 ka河流阶地年龄数据的处理,发现存在7个明显的河流阶地发育时期,即150、100、70、40、30、12和6 ka B.P.。经过相关构造和气候资料的论证,文章认为,在150和70 ka B.P.附近形成的两级河流阶地代表了河西地区...文章通过对河西地区最近150 ka河流阶地年龄数据的处理,发现存在7个明显的河流阶地发育时期,即150、100、70、40、30、12和6 ka B.P.。经过相关构造和气候资料的论证,文章认为,在150和70 ka B.P.附近形成的两级河流阶地代表了河西地区两期主要的构造抬升,而在100、40、30、12和6 ka B.P.附近形成的5级河流阶地则对应于河西地区5期气候变化事件。展开更多
文摘The effects of rigid vegetation on the turbulence characteristics were experimentally studied in the interior water flume. An ADV was used to determine the three dimensional turbulent velocities in clear water flow without vegetation, sediment-laden flow without vegetation, sediment-laden flow with submerged vegetation and sediment-laden flow with non-submerged vegetation. By experimental and theoretical analysis, the effects of rigid vegetation on the distribution of averaged velocities, turbulence intensities and Reynolds stress were summarized. In sediment-laden flow with submerged vegetation, the averaged stream wise velocities above the top of vegetation fit well with the log distribution low. The three-dimensional turbulence intensities increase from the bottom until they reach the maximum at the top of the vegetation. The method to calculate the shear velocity with the maximum of the Reynolds stress is recommended. In sediment-laden flow with non-submerged vegetation, the turbulence problems cannot be explained by theory of bed shear flow. The average velocities, turbulence intensities and Reynolds stress approximate uniformly distributed along vertical direction.
文摘文章通过对河西地区最近150 ka河流阶地年龄数据的处理,发现存在7个明显的河流阶地发育时期,即150、100、70、40、30、12和6 ka B.P.。经过相关构造和气候资料的论证,文章认为,在150和70 ka B.P.附近形成的两级河流阶地代表了河西地区两期主要的构造抬升,而在100、40、30、12和6 ka B.P.附近形成的5级河流阶地则对应于河西地区5期气候变化事件。
