The Role of Fluctuating Fluid Forces on the Initiation of Sediment Motion

脉动流体力对沉积物运动引发的作用

• 批准号: 0439663
• 负责人: Panos Diplas
• 金额: $ 38万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0439663&HistoricalAwards=false
• 关键词: Role; Fluctuating; Fluid; Forces; Initiation

The goal of this project is to determine the key parameters responsible for sediment dislodgement under the influence of fluctuating hydrodynamic forces, typically encountered in turbulent flows. Experiments are proposed to examine the role of force-time history (impulse) and inertia forces on particle entrainment at near threshold conditions. The experiments will be performed in an existing research flume, where the forces on an isolated spherical particle will be measured using an instrumented spherical test grain custom designed and fabricated (magnetic) such that a limited set of fully time-resolved surface pressures can be measured. The effects of viscous drag, inertia, and impulse on sediment entrainment will be explored through experiments including no motion, steady uniform turbulent motion and spatially accelerating turbulent motion. During the experiments digital video photography and acoustic Doppler sensors (for the hydraulic tests) will be used to monitor the target particle movement as demonstrated in recent pilot tests. Developing more universal criteria for threshold of motion conditions will improve existing engineering methods for the design of stable waterways and establish better risk-based methods for preventing the removal of contaminated sediments.

该项目的目标是确定在湍流中通常遇到的波动水动力影响下负责沉积物移动的关键参数。 实验提出了检查的作用，力-时间的历史（脉冲）和惯性力颗粒夹带在近阈值条件。实验将在现有的研究水槽中进行，其中孤立的球形颗粒上的力将使用定制设计和制造（磁性）的仪表球形测试颗粒进行测量，以便可以测量有限的一组完全时间分辨的表面压力。 通过无运动、定常均匀紊流运动和空间加速紊流运动的试验，探讨了粘性阻力、惯性和冲量对挟沙的影响。在实验过程中，数字视频摄影和声学多普勒传感器（用于水力测试）将用于监测目标颗粒的运动，正如最近的试点测试所证明的那样。 制定更普遍的运动条件阈值标准将改进现有的稳定水道设计工程方法，并建立更好的基于风险的方法，以防止污染沉积物的清除。