Sediment mass movement of a particle-laden turbidity current based on ultrasound velocity profiling and the distribution of sediment concentration
Sediment mass movement of a particle-laden turbidity current based on ultrasound velocity profiling and the distribution of sediment concentration
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基于超声速度剖面和泥沙浓度分布的含颗粒浊流的泥沙质量运动
DOI：
10.1144/sp477.19
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Sakaguchi Hide
中科院分区：
文献类型：
--
作者：
Nomura Shun;Hitomi Jumpei;De Cesare Giovanni;Takeda Yasushi;Yamamoto Yuzuru;Sakaguchi Hide
沿着海底的颗粒流或浊流对于海底地形的形成和侵蚀很重要。为了了解质量传输过程，我们通过连续供应含有石英的悬浮液进行了水槽测试。通过相对于床法线方向以不同角度安装的两对超声多普勒速度剖面仪提取垂直和水平速度。由于头部侵入环境水中，悬浮液中的沉积物不断被提升并混合，留下裂片和裂缝。最大速度层作为主要的泥沙输送带，将主体分为壁面区和射流区。还根据使用视频记录获得的流体密度和光衰减强度之间的关系来量化浓度分布。在头部额叶区域后面观察到沉积物浓度高的区域。速度和浓度分布分析表明，浊流中泥沙主要通过水头运动输送，在壁区发生连续沉降。结果表明，浊流在保持有序的内部动态结构的同时进行。
Particle-laden flows or turbidity currents along the seafloor are important to the formation and erosion of submarine topography. To understand the mass-transport process, flume tests were carried out with a continuous supply of quartz-laden suspension. The vertical and horizontal velocities were extracted by two pairs of ultrasound Doppler velocity profilers installed at different angles with respect to the bed-normal direction. Due to the head intrusion into the ambient water, the sediment in the suspension was continuously lifted up and mixed, leaving lobes and clefts. The velocity-maximum layer acted as the main sediment conveyor and divided the body into wall and jet regions. The concentration distribution was also quantified based on the relationship between the fluid density and the intensity of light attenuation obtained using a video recording. An area of high sediment concentration was observed just behind the head frontal area. Analysis of the velocity and concentration distribution demonstrated that sediment in the turbidity current was transported mainly by head movement and that continuous sedimentation took place in the wall region. The results indicate that a turbidity current proceeds while maintaining an ordered inner dynamic structure.