| Velocity and Sediment Concentration Profiles in Sediment-Laden Flows |
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| 作者姓名： | 杨树清 Soon-KeatTAN Siow-YongLIM |
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| 作者单位： | [1]MaritimeResearchCenter,NanyangTechnologicalUniversity,Singapore639798 [2]SchoolofCivilandEnvironmentalEngineering,NanyangTechnologicalUniversity,Singapore639798 |
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| 摘 要： | A theoretical analysis of velocity profiles in sediment-laden flows is presented by means of Prandtl-Karman mixing length theorem. The study shows that the upward velocity of liquid-phase caused by settling sediment leads to the invalidity of the log-law and Rouse equation. The theoretical analysis takes into account the upward velocity and shows: 1) the mean velocity in sediment-laden flows follows the log-law, but the Karman constant reduces in the main flow region, 2) sediment concentration reduces the mixing length of fluid particles, 3) flow resistance reduces with the presence of sediment concentration, and 4) the sediment concentration profile deviates from the well know Rouse equation. The experimental data agree well with the equations derived on the basis of non-zero wall velocity. It is found that the wall-normal velocity should not be neglected for density gradient flows because it induces more than for pure water flows.
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| 关 键 词： | 沉积浓度 卡曼常量 流体力学 密度梯度 |
Velocity and Sediment Concentration Profiles in Sediment-Laden Flows |
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| Shu-qing YANG a,Soon-Keat TAN a,b and Siow-Yong LIMb a Maritime Research Center,Nanyang Technological University,Singapore b School of Civil and Environmental Engineering,Nanyang Technological University,Singapore.Velocity and Sediment Concentration Profiles in Sediment-Laden Flows[J].China Ocean Engineering,2004,18(2):229-244. |
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| Authors: | Shu-qing YANG a Soon-Keat TAN a b and Siow-Yong LIMb a Maritime Research Center Nanyang Technological University Singapore b School of Civil and Environmental Engineering Nanyang Technological University Singapore |
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| Institution: | Shu-qing YANG a,1,Soon-Keat TAN a,b and Siow-Yong LIMb a Maritime Research Center,Nanyang Technological University,Singapore 639798 b School of Civil and Environmental Engineering,Nanyang Technological University,Singapore 639798 |
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| Abstract: | A theoretical analysis of velocity profiles in sediment-laden flows is presented by means of Prandtl-Karman mixing length theorem. The study shows that the upward velocity of liquid-phase caused by settling sediment leads to the invalidity of the log-law and Rouse equation. The theoretical analysis takes into account the upward velocity and shows: 1) the mean velocity in sediment-laden flows follows the log-law, but the Karman constant reduces in the main flow region, 2) sediment concentration reduces the mixing length of fluid particles, 3) flow resistance reduces with the presence of sediment concentration, and 4) the sediment concentration profile deviates from the well know Rouse equation. The experimental data agree well with the equations derived on the basis of non-zero wall velocity. It is found that the wall-normal velocity should not be neglected for density gradient flows because it induces more than for pure water flows. |
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| Keywords: | sediment concentration reduction of Karman constant log-law sediment concentration distribution |
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