On the numerical modelling of the Hole Erosion Test

Mercier, Fabienne; Bonelli, Stéphane; Philippe, Pierre; Golay, Frédéric; Anselmet, Fabien; Pinettes, Patrick; Fry, Jean Jacques

doi:10.1201/b17703-39

Cited by 5 publications

(7 citation statements)

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“…This capability is especially important for two-phase flow problems in which the time scales of the various phases can be significantly different. More specifically, the flow time scale for our case, and for most geophysical flow applications, is significantly smaller than the time scale of bed morphodynamics [73]. Dimensional analysis of the governing equations for flow and morphodynamics show that the erosion kinetics are significantly slower than the flow kinetics and that the time scale of bed change is approximately two orders of magnitude greater than that of the flow field [73].…”

Section: Variable Time-stepping Techniquementioning

confidence: 82%

“…More specifically, the flow time scale for our case, and for most geophysical flow applications, is significantly smaller than the time scale of bed morphodynamics [73]. Dimensional analysis of the governing equations for flow and morphodynamics show that the erosion kinetics are significantly slower than the flow kinetics and that the time scale of bed change is approximately two orders of magnitude greater than that of the flow field [73]. From a practical point of view, it is also important to have the capability of utilizing two different time steps for the flow and bed-change calculations as the mobile bed of a natural waterway requires integration over a very long physical time to reach quasi-equilibrium.…”

Section: Variable Time-stepping Techniquementioning

confidence: 98%

“…(i) Most methods employ the ALE approach, which requires that the grid conforms to the boundary shape at all times. This requirement restricts the application of such methods to simulations of small amplitude bed forms for which the mesh deformation remains small at all times (for more details see [64]); and (ii) The time scale for the sediment transport process is about two orders of magnitude greater than that of the instantaneous turbulent flow field [73]. Given this different in time scale, the coupled simulation of large-scale bed form evolution, which could take up to months of physical time, can be extremely expensive regardless of the underlying numerical approach.…”

Section: Introductionmentioning

confidence: 99%

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Numerical simulation of large dunes in meandering streams and rivers with in-stream rock structures

Khosronejad

Kozarek

Palmsten

et al. 2015

Advances in Water Resources

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The evolution and migration of large dunes in a realistic intermediate-size experimental stream, the Saint Anthony Falls Laboratory (SAFL) Outdoor StreamLab (OSL), and two large-scale meandering rivers with in-stream rock structures are studied numerically using the SAFL Virtual StreamLab hydro-morphodynamic (VSL3D) model. Due to the challenges arising from mesh quality and large disparity in timescales , coupled morphoand hydro-dynamics simulations of bed forms has, for the most part, been restricted to sand wave amplitudes of few centimeters. In this work, we overcome such difficulties by employing the immersed boundary approach and a dual time-stepping technique of the VSL3D model [63]. The VSL3D employs the curvilinear immersed boundary (CURVIB) method along with a suspended sediment load module and is capable of simulating turbulent stratified flows coupled with bed morphodynamic evolution in realistic riverine environments with arbitrarily complex hydraulic structures. Turbulence is handled either via large-eddy simulation (LES) with the dynamic Smagorinski subgrid scale model or unsteady Reynolds-averaged Navier Stokes (URANS) equations closed with the k − ω turbulence model. Simulations in the intermediate-scale OSL channel, in which we also collected experimental morphodynamic data, show that LES can capture the evolution and migration of bed forms with characteristics that are in good agreement with experimental measurements. The URANS model, however, fails to excite the bed instability in the OSL channel but captures realistic dune evolution in the two large-scale meandering rivers. This finding is especially important as it demonstrates the potential of the VSL3D model as a powerful tool for simulating morphodynamic evolution under prototype conditions. To our knowledge, our work is the first attempt to simulate large-scale bed forms in waterways with an order of magnitude disparity in spatial scales, from the ∼ 2.7m wide OSL channel to the 27m wide rivers. Accordingly, the height of the simulated dunes ranges from ∼ 0.2m to 2.0m and the wavelength ranges from ∼ 0.1m to 50m for the OSL and large-scale rivers, respectively. For all cases the statistical properties of the simulated bed forms are shown to agree well with those of bed forms observed in nature.

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Section: Variable Time-stepping Techniquementioning

confidence: 82%

Section: Variable Time-stepping Techniquementioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical simulation of large dunes in meandering streams and rivers with in-stream rock structures

Khosronejad

Kozarek

Palmsten

et al. 2015

Advances in Water Resources

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“…Using the loose-coupling FSI approach for flow-bed interactions with the assumption that the bed surface geometry, rate of change of the bed surface, and concentration fields of flow and suspended sediment are available at time step 𝐴𝐴 𝐴𝐴 , we use the following algorithm to solve for the flow field and bed morphodynamics at time step Finally, a key aspect of the simulations is that we employ different time steps to match the hydrodynamic and morphodynamic modules of the code with respect to time. Given that, for most applications in geophysical flows, the characteristic time scale of the morphodynamics is an order of magnitude larger than that of the hydrodynamics (Mercier et al, 2012), different time steps for the flow and morphodynamics alleviate the high computational costs of the coupled simulations. More specifically, for river simulations, the coupled system of flow and morphodynamics should be run long enough to obtain the dynamic equilibrium bed morphology covering the time scale of the morphodynamic evolution.…”

Section: Coupling Of Hydrodynamics and Morphodynamicsmentioning

confidence: 99%

On the Morphodynamics of a Wide Class of Large‐Scale Meandering Rivers: Insights Gained by Coupling LES With Sediment‐Dynamics

Khosronejad

Limaye

Zhang

et al. 2023

J Adv Model Earth Syst

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Rivers are the focal points of human society and Earth systems. Rivers are vital corridors for shipping, manufacturing, agriculture, and recreation. Water-borne pollutants, as well as those carried in sediments, are deposited during floods, impact surfaces and groundwater quality. Rivers are the primary habitat for aquatic species and provide an indispensable ecosystem for riparian species. Rivers transport enormous quantities of sediments and solutes from continents to the ocean (Syvitski & Milliman, 2007), shaping continental surfaces and coastlines,

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“…We can clearly identify two types of numerical modeling frameworks. In the first type, numerical models apply computational fluid dynamics (CFD) software for computing the fluid motion only above the bed [1,[25][26][27]. The second modeling framework is based on two-phase approaches, in which the motion equations solve both solid and fluid phases [28][29][30][31][32][33][34][35].…”

mentioning

confidence: 99%

Two-Phase Flow Modeling for Bed Erosion by a Plane Jet Impingement

Bang

Zapata

Gauthier

et al. 2022

Water

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This paper presents experimental and numerical studies on the erosion of a horizontal granular bed by a two-dimensional plane vertical impinging jet to predict the eroded craters’ size scaling (depth and width). The simulations help understand the microscopic processes that govern erosion in this complex flow. A modified jet-bed distance, accounting for the plane jet virtual origin, is successfully used to obtain a unique relationship between the crater size and a local Shields parameter. This work develops a two-phase flow numerical model to reproduce the experimental results. The numerical techniques are based on a finite volume formulation to approximate spatial derivatives, a projection technique to calculate the pressure and velocity for each phase, and a staggered grid to avoid spurious oscillations. Different options for the sediment’s solid-to-liquid transition during erosion are proposed, tested, and discussed. One model is based on unified equations of continuum mechanics, others on modified closure equations for viscosity or momentum transfer. A good agreement between the numerical solutions and the experimental measurements is obtained.

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On the numerical modelling of the Hole Erosion Test

Cited by 5 publications

References 0 publications

Numerical simulation of large dunes in meandering streams and rivers with in-stream rock structures

Numerical simulation of large dunes in meandering streams and rivers with in-stream rock structures

On the Morphodynamics of a Wide Class of Large‐Scale Meandering Rivers: Insights Gained by Coupling LES With Sediment‐Dynamics

Two-Phase Flow Modeling for Bed Erosion by a Plane Jet Impingement

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