Assessment of Turbulence Models on Bridge-Pier Scour Using Flow-3D

Man, Chandara; Zhang, Genguang; Hong, Vouchleang; Zhou, Shuang; Feng, Yulin

doi:10.4236/wjet.2019.72016

Cited by 17 publications

(6 citation statements)

References 32 publications

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“…For three-dimensional analysis of an incompressible fluid state within the Flow-3D software, the Reynolds-Averaged Navier-Stokes (RANS) equations in the Cartesian coordinate system are employed, as outlined by (Man et al 2019):…”

Section: Reynolds Average Navier-stokesmentioning

confidence: 99%

Numerical Modeling of Downstream Scour in Circular Culverts: Impact of Inlet Blockages and Variable Flow Conditions

Ahmed,

Kavianpour,

Amini

et al. 2024

Preprint

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Accurate estimation of scour depth downstream of culvert outlets is essential for culvert design integrity. Inadequate designs can result in structural failures, leading to increased costs for maintenance and rehabilitation. This research evaluates the efficacy of numerical models in predicting scour depth and its location downstream of circular culverts under variable flow conditions. Two hydrographs were created for unsteady flow, featuring nine different flow discharges, while steady flow conditions were analysed at flow rates of 14 l/s and 22 l/s. The study investigated circular culverts with inlet blockages of 0%, 15%, and 30%, comparing outcomes with predictions from the Flow-3D software by using renormalization group (RNG) turbulence model. Extensive experimental data on circular culverts were utilized, with simulations performed using commercial software. This involved analysing the scour’s downstream profile, its maximum depth, and location, and comparing these metrics with actual observed data. Results showed that numerical model predictions closely matched the experimental data, although the simulated scour was generally less than what was observed for both steady and unsteady flows. While blockage rates notably impacted the scour patterns in unsteady flow scenarios, escalating blockage percentages did not uniformly translate into proportional increases in scour depth within steady flow environments.

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Section: Reynolds Average Navier-stokesmentioning

confidence: 99%

Numerical Modeling of Downstream Scour in Circular Culverts: Impact of Inlet Blockages and Variable Flow Conditions

Ahmed,

Kavianpour,

Amini

et al. 2024

Preprint

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show abstract

“…The results were compared with those of the experimental model of Melville Laboratory. The findings indicated that the proposed Flow-3D model was an effective tool for predicting and simulating scour depths around bridge piers and an economical method for predicting the potential outcomes.Man, C., In a subsequent study, et al [28] investigated the impact of distinct turbulence modes on the formation of bridge pier scour pits within the Flow-3D software. The simulated scour results were found to diverge significantly from the observed data collected from previous literature, due to the non-applicability of the meshing method in the Flow-3D software.…”

Section: Preprintsmentioning

confidence: 99%

Optimization of bridge pier winding flow numerical simulation scheme based on Delft3D

Xiao,

Qingsheng,

Zhaoning

et al. 2024

Preprint

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The majority of existing numerical simulations of the effect of bridge piers on water movement are based on a limited number of bridge piers at a laboratory scale. Furthermore, some 2D numerical simulations for actual bridge projects have deficiencies, including the use of overly large mesh sizes and an inadequate treatment of bridge piers. In this study, we compare three methods of structural mesh encryption, suspension mesh, and nonstructural mesh based on Delft3D, and apply the optimization scheme to a real bridge project. It is demonstrated that optimal results can be achieved by utilising a grid size comparable to the pier diameter (Dp) in the region away from the piers. In the vicinity of the piers, the grid cell size should be no larger than 1/9 Dp. The suspended grid technique (DD Boundary) can yield results consistent with those obtained using a full-area high-resolution grid, provided that the total number of grids can be reduced and the computational time is considerably reduced. In this study, the unstructured mesh (Deflt3D Flexible Mesh) scheme was unable to capture the oscillations of the wake flow behind the bridge piers. However, the application of the optimized scheme in bridge engineering has demonstrated its practical value. The findings of this study on mesh resolution and suspension mesh scheme can be applied to the Delft3D software and are also useful for other numerical simulation work.

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“…In contrast, the LES model showed acceptable values of R 2 , while the NSE (0.423) was found to be less than RNG K-model. The deviation in scour profile by LES can be due to (1) the LES model being mesh-dependent, which requires finer cell size in the turbulent flow zones to capture the small scale fluctuations, i.e., turbulent eddies, and (2) within the scour hole, strong vertexes are generated, for which the model employed a sub-grid turbulence model, which captured small eddies in the scour hole and consequently increased the scour depth and overall retrogression on the downside of the sediment bed, as stated by Man et al [56] and Hamid et al [57]. In contrast, due to the limitation in computing the wake velocities in the shear region, the RNG K-model predicted less scour in the scour hole and on the downward areas.…”

Section: Model Verification and Validationmentioning

confidence: 99%

Performance Evaluation of Different Stilling Basins Downstream of Barrage Using FLOW-3D Scour Models

Zaffar,

Haasan,

Ghumman

2023

Hydrology

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The present study investigated the performance of three different stilling basins, i.e., modified United State Bureau of Reclamation (USBR) Type III, USBR Type II, and wedge-shaped baffle blocks (WSBB), using FLOW-3D scour models. Field data of the riverbed profile are employed to validate the present models. After comparison, the results of statistical indices, i.e., coefficient of determination (R2) and Nash–Sutcliffe model efficiency coefficient (NSE), indicated that the Renormalization Group (RNG-K-ϵ) showed good agreement with the field data, with R2 and NSE values of 0.9094 and 0.896, respectively. Validated models are used to simulate velocity field and local bed shear stress (BSS) and scour for design and flood discharges of 28.30 m3/s/m and 17.5 m3/s/m, respectively. At 28.30 m3/s/m, the results indicated that the riverbed downstream of the remodeled basin was completely exposed, while, at 17.5 m3/s/m, the net change in bed reached 85%. At 28.30 m3/s/m, the net change at the centerline of models reached 51% and 67% in USBR Type III and WSBB basins, respectively. At 17.5 m3/s/m, compared to Type II and III basins, the WSBB basin indicated less BSS, which significantly reduced the scour. Conclusively, the Type II basin showed less energy dissipation for the studied flows, while the WSBB basin improved flow fields downstream of the barrage.

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Assessment of Turbulence Models on Bridge-Pier Scour Using Flow-3D

Cited by 17 publications

References 32 publications

Numerical Modeling of Downstream Scour in Circular Culverts: Impact of Inlet Blockages and Variable Flow Conditions

Numerical Modeling of Downstream Scour in Circular Culverts: Impact of Inlet Blockages and Variable Flow Conditions

Optimization of bridge pier winding flow numerical simulation scheme based on Delft3D

Performance Evaluation of Different Stilling Basins Downstream of Barrage Using FLOW-3D Scour Models

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