基于水下摄影的床面泥沙运动特性试验研究

Translated title of the contribution: Experimental study on the property of bed load motion based on the underwater photography technology

Mingxiao Liu, Michele Guala, Dongpo Sun

Research output: Contribution to journalArticlepeer-review

Abstract

In order to improve the observation accuracy and efficiency of bed load experiments, the fine experimental observations of the movement and the state transition of bed sands in open channel flow were accomplished by means of underwater photography and particle tracking (UP/PTV). The reliability of the sampling data was improved by removing the interference caused by bed sands wagging, and setting the critical threshold of particle motion state as well as adapting multiple filter screening programs. By conducting series of bed load experiments under low transport intensity conditions, data including motion trajectory, velocity and step duration of bed particle was obtained, which was analyzed using a Lagrange process and the Probability Density Function (PDF) of the particle motion elements. Experimental results indicated that, the particle velocity shows a trend that increases rapidly at first and then decays slowly during the process of one single step, which is caused by inter particle collision and sweep events of near-bed turbulence. The PDF curve of particle velocity presents the Gamma function distribution with a thin tail, while the PDF curve of particle acceleration shows the Laplace distribution characteristics, influenced by the particle wagging effect. The particle velocity is closely associated with the friction velocity u*, maintaining a ratio of 3.4 to 3.5. The joint distribution of the single step duration Ts and the single step length Ls of the particles presents an exponential function, and the exponent of the fitting curves ranges between 1.25 and 1.30. The exponent is associated with the transport intensity of bed load and the heterogeneity of the bed surface particles.

Translated title of the contributionExperimental study on the property of bed load motion based on the underwater photography technology
Original languageChinese (Traditional)
Pages (from-to)449-457
Number of pages9
JournalShuikexue Jinzhan/Advances in Water Science
Volume32
Issue number3
DOIs
StatePublished - May 30 2021

Bibliographical note

Funding Information:
The study is financially supported by the National Natural Science Foundation of China (No. 51909093; No. 52079032).

Publisher Copyright:
© 2021, Editorial Board of Advances in Water Science. All right reserved.

Keywords

  • Active waiting
  • Bed sand
  • Particle state
  • Particle tracking technology
  • Thin tailed distribution
  • Underwater photograph

Fingerprint

Dive into the research topics of 'Experimental study on the property of bed load motion based on the underwater photography technology'. Together they form a unique fingerprint.

Cite this