Hybrid Artificial Viscosity–Central-Upwind Scheme for Recirculating Turbulent Shallow Water Flows

Ginting, Bobby Minola; Ginting, Herawaty

doi:10.1061/(asce)hy.1943-7900.0001639

Cited by 11 publications

(3 citation statements)

References 54 publications

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“…The FV3 predicted velocity vectors exhibit short vortex street, with spurious vortices detaching and spreading asymmetrically in the far wake region. In contrast, those predicted by the DG2 solver are consistent with the patterns predicted by a more complex 2D depth-averaged Reynolds-averaged Navier-Stokes model(Ginting and Ginting, 2019).…”

supporting

confidence: 71%

“…The island has a height of 0.049 m, a side slope of 8.0 degrees, and a diameter of 0.05 and 0.75 m at the top and base of the conical island, respectively. A unidirectional inflow velocity of u = 0.115 m/s inundates the island until it becomes fully submerged under a water depth of 0.054 m. The DG2 solver was run until 500 s at the grid resolution of 0.0152 m (medium), specified by Lloyd and Stansby (1997) Existing studies already uncovered the weakness of the FV2 solver to capture vortex formation past a cylindrical obstacle with reference to depth-integrated solvers including more complex turbulence models (e.g., Kim et al 2009;NTHMP 2016;Ginting and Ginting 2019). The FV2 solver predictions lead to significantly elongated recirculation length with slower velocity recovery rate past the obstacle, but these shortcomings can be improved with the DG2 solver predictions (Sun et al 2022).…”

Section: Vortex Shedding Past a Conical Islandmentioning

confidence: 99%

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Shallow-Flow Velocity Predictions Using Discontinuous Galerkin Solutions

et al. 2023

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Numerical solvers of the two-dimensional (2D) shallow water equations (2D-SWE) can be an efficient option to predict spatial distribution of velocity fields in quasi-steady flows past or throughout hydraulic engineering structures. A second-order finite volume solver (FV2) spuriously elongates small-scale recirculating eddies within its predictions, unless sustained by an artificial eddy viscosity, while a third-order finite volume (FV3) solver can distort the eddies within its predictions. The extra complexity in a second-order discontinuous Galerkin (DG2) solver leads to significantly reduced error dissipation and improved predictions at a coarser resolution, making it a viable contender to acquire velocity predictions in shallow flows. This paper analyses this predictive capability for a grid-based, open source DG2 solver with reference to FV2 or FV3 solvers for simulating velocity magnitude and direction at the sub-meter scale. The simulated predictions are assessed against measured velocity data for four experimental test cases. The results consistently indicate that the DG2 solver is a competitive choice to efficiently produce more accurate velocity distributions for the simulations dominated by smooth flow regions. Practical ApplicationsThe estimation of the spatial distribution of horizontal velocity fields is useful to analyse the design of hydraulic and flood-defence structures undergoing shallow water flow processes. Examples include flooding through a residential area with piered buildings where recirculation flow eddies occur within side cavities, past building blocks, and across of street junctions. This paper demonstrates the utility of a relatively new hydraulic simulation tool, so-called DG2 solver, as an alternative to existing finite volume solvers featured in popular tools such as HEC-RAS 2D, Rubar20, Iber and TUFLOW-HPC. The DG2 solver is open source, as part of the LISFLOOD-FP 8.0 software suite, and particularly excels in the estimation of velocity fields that are more informative of the flow processes within a few minutes of simulation time. The proposed simulation tool is limited to modelling problems where the depth-integrated assumption of the shallow water equations is appropriate.

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confidence: 71%

Section: Vortex Shedding Past a Conical Islandmentioning

confidence: 99%

Shallow-Flow Velocity Predictions Using Discontinuous Galerkin Solutions

et al. 2023

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“…The rainfall-runoff computations were performed in this research in the framework of an in-house code NUFSAW2D (Numerical Simulation of Free Surface Shallow Water 2D) developed by the author of this paper. This code has been tested and proven accurate in several works [15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Artificial viscosity technique for direct runoff calculation

Ginting

2023

E3S Web Conf.

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In this study, an Artificial Viscosity (AV) technique was developed for direct runoff calculation, instead of using the conventional Synthetic Unit Hydrograph (SUH) methods. We solved the Shallow Water Equations (SWE) with second-order accurate Godunov finite volume model and fourth-order Runge-Kutta explicit scheme. The AV technique was devised with a Laplacian and a biharmonic operator, and employed to solve the convective terms of the SWE. This technique was applied to rainfall-runoff laboratory cases with the measured rainfall and observed direct runoff values. For comparison purpose, several SUH methods commonly used such as SCS, Snyder, GAMA-1, ITB-1, ITB-2, and Nakayasu, were also used to compute the direct runoff values. The results showed that the AV technique could predict three parameters (i.e., peak discharge, time-to-peak, and shape of the direct runoff hydrograph) accurately. Meanwhile, significant discrepancies were shown by the SUH methods in estimating such parameters, thus indicating that the SWE modeling with an AV technique is significantly more accurate than the SUH methods in predicting the direct runoff hydrograph. This study shows an interesting example of how modern numerical computations can improve the runoff prediction and may be included as a standard technique for runoff computation in the future.

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