Fractal scaling and simulation of velocity components and turbulent shear stress in open channel flow

A weakly compressible smoothed particle hydrodynamics (WCSPH) method was developed to model open-channel flow over rough bed. An improved boundary treatment is proposed to quantitatively characterize bed roughness based on the ghost boundary particles (GBPs). In this model, the velocities of GBPs are explicitly calculated by using evolutionary polynomial regression with a multiobjective genetic algorithm. The simulation results show that the proposed boundary treatment can well reflect the influence of wall roughness on the vertical flow structure. A fully developed open channel is established, and its flume length, processing time, and turbulent model are discussed. The mixed-length-based subparticle scale (SPS) turbulence model is adopted to simulate uniform flow in open channel, and this model is compared with the Smagorinsky-based one. For the modified WCSPH model, the results show that the calculated vertical velocity and turbulent shear stress distribution are in good agreement with experimental data and fit better than the calculations obtained from the traditional Smagorinsky-based model.

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Groyne spacing role on the effective control of wall shear stress in open-channel flow

Journal of Hydraulic Research ◽

10.1080/00221686.2018.1478895 ◽

2018 ◽

Vol 57 (2) ◽

pp. 167-182 ◽

Cited By ~ 1

Author(s):

Theofano I. Koutrouveli ◽

Athanassios A. Dimas ◽

Nikolaos Th. Fourniotis ◽

Alexander C. Demetracopoulos

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Channel Flow ◽

Open Channel ◽

Open Channel Flow ◽

Effective Control ◽

Wall Shear

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Near-bed velocity and shear stress of open-channel flow over surface roughness

Environmental Fluid Mechanics ◽

10.1007/s10652-019-09728-3 ◽

2020 ◽

Vol 20 (2) ◽

pp. 293-320 ◽

Cited By ~ 1

Author(s):

Jing Li ◽

S. Samuel Li

Keyword(s):

Surface Roughness ◽

Shear Stress ◽

Channel Flow ◽

Open Channel ◽

Open Channel Flow

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Vertical distribution of shear stress in unsteady open-channel flow

Proceedings of the Institution of Civil Engineers - Water Maritime and Energy ◽

10.1680/iwtme.1992.09807 ◽

1992 ◽

Vol 96 (2) ◽

pp. 63-69 ◽

Cited By ~ 1

Author(s):

Haizhou Tu ◽

W. H. Graf

Keyword(s):

Shear Stress ◽

Vertical Distribution ◽

Channel Flow ◽

Open Channel ◽

Open Channel Flow

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Flow Partitioning in Rectangular Open Channel Flow

Mathematical Problems in Engineering ◽

10.1155/2018/6491501 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7

Author(s):

Yu Han ◽

Shu-Qing Yang ◽

Muttucumaru Sivakumar ◽

Liu-Chao Qiu ◽

Jian Chen

Keyword(s):

Shear Stress ◽

Channel Flow ◽

Open Channel ◽

Laser Doppler Anemometry ◽

Reynolds Shear Stress ◽

Three Dimensional ◽

Open Channel Flow ◽

Flow Region ◽

Mathematical Tool ◽

Measured Velocity

Hydraulic engineers often divide a flow region into subregions to simplify calculations. However, the implementation of flow divisibility remains an open issue and has not yet been implemented as a fully developed mathematical tool for modeling complex channel flows independently of experimental verification. This paper addresses whether a three-dimensional flow is physically divisible, meaning that division lines with zero Reynolds shear stress exist. An intensive laboratory investigation was conducted to carefully measure the time-averaged velocity in a rectangular open channel flow using a laser Doppler anemometry system. Two innovative methods are employed to determine the locations of division lines based on the measured velocity profile. The results clearly reveal that lines with zero total shear stress are discernible, indicating that the flow is physically divisible. Moreover, the experimental data were employed to test previously proposed methods of calculating division lines, and the results show that Yang and Lim’s method is the most reasonable predictor.

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