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On the turbulent flow structure around an instream structure with realistic geometry

Title
On the turbulent flow structure around an instream structure with realistic geometry
Author
강석구
Keywords
stream restoration; turbulence
Issue Date
2016-10
Publisher
AMER GEOPHYSICAL UNION
Citation
WATER RESOURCES RESEARCH, v. 52, NO. 10, Page. 7869-7891
Abstract
We investigate the flow dynamics around a rock vane, a widely used instream structure for stream restoration, by conducting laboratory flume experiments, and carrying out high-resolution Large Eddy Simulation (LES) taking advantage of parallel computing. The flume experiments are conducted under fixed- and mobile-bed conditions, where the velocities and bed elevations are measured, respectively. The LES is carried out for the fixed-bed experiment by directly resolving the details of the rocks that constitute the vane and the individual roughness elements on the channel bed. The LES-computed mean flow statistics show good agreement with the measurements, and the analysis of the computed flow field reveals the existence of two counter-rotating secondary flow cells downstream of the vane, which originate from the plunging of the three-dimensional streamlines onto a lower part of the sidewall downstream of the vane. To further examine the role of the secondary flow cells under a mobile-bed condition, the LES results are compared with the equilibrium bed elevation measured in the mobile bed experiment. The mobile-bed experiment reveals the existence of an oblique sand ridge downstream of the vane that is aligned with the line of flow convergence caused by the collision of the two secondary flow cells. The results indicate that the two counter-rotating cells downstream of the rock vane has a profound impact on the mean flow and bed shear stress as well as on the bed morphodynamics.
URI
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016WR018688https://repository.hanyang.ac.kr/handle/20.500.11754/98861
ISSN
0043-1397; 1944-7973
DOI
10.1002/2016WR018688
Appears in Collections:
COLLEGE OF ENGINEERING[S](공과대학) > CIVIL AND ENVIRONMENTAL ENGINEERING(건설환경공학과) > Articles
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