scholarly journals Modelling of scour formation using SedFoam, continuum approach

2021 ◽  
Vol 249 ◽  
pp. 03038
Author(s):  
Alaa Ghzayel ◽  
Anthony Beaudoin ◽  
Sebastien Jarny

SedFOAM is a two-phase flow solver built upon consecutive laws, based on the CFD toolbox OpenFOAM. The sediment body is considered as a continuum phase. The intergranular and fluid stresses are modeled with the dense granular flow rheology and the k–ϵ turbulent model, respectively. The model setup will be based on an experimental study on the scour due to a water jet subjected to lateral confinement. A comparison study will be made based on precise experimental data by Martino et al. (2019) that will show the advantages and defaults of SedFoam. The objective of this work is to reproduce the digging and filling cycle of the scour formation due to the water jet in a confined canal. The first numerical results show that it needs to use 3D numerical simulations because of the fluctuation of the jet direction induced by the presence of a driven flow cavity.

2017 ◽  
Author(s):  
Julien Chauchat ◽  
Zhen Cheng ◽  
Tim Nagel ◽  
Cyrille Bonamy ◽  
Tian-Jian Hsu

Abstract. In this paper, a three-dimensional two-phase flow solver, SedFoam-2.0, is presented for sediment transport applications. The solver is extended upon twoPhaseEulerFoam available in the 2.1.0 release of the open-source CFD toolbox OpenFOAM. In this approach the sediment phase is modeled as a continuum, and constitutive laws have to be prescribed for the sediment stresses. In the proposed solver, two different inter-granular stress models are implemented: the kinetic theory of granular flows and the dense granular flow rheology μ(I). For the fluid stress, laminar or turbulent flow regimes can be simulated and three different turbulence models are available for sediment transport: a simple mixing length model (one-dimensional configuration only), a k-ϵ and a k-ω model. The numerical implementation is first demonstrated by two validation test cases, sedimentation of suspended particles and laminar bed-load. Two applications are then investigated to illustrate the capabilities of SedFoam-2.0 to deal with complex turbulent sediment transport problems with different combinations of inter-granular stress and turbulence models.


Author(s):  
Alessandro Tasora ◽  
Mihai Anitescu

Aiming at the simulation of dense granular flows, we propose and test a numerical method based on successive convex complementarity problems. This approach originates from a multibody description of the granular flow: all the particles are simulated as rigid bodies with arbitrary shapes and frictional contacts. Unlike the discrete element method (DEM), the proposed approach does not require small integration time steps typical of stiff particle interaction; this fact, together with the development of optimized algorithms that can run also on parallel computing architectures, allows an efficient application of the proposed methodology to granular flows with a large number of particles. We present an application to the analysis of the refueling flow in pebble-bed nuclear reactors. Extensive validation of our method against both DEM and physical experiments results indicates that essential collective characteristics of dense granular flow are accurately predicted.


2012 ◽  
Vol 229-231 ◽  
pp. 559-564
Author(s):  
Hong Hua ◽  
Xiao Lin Wang ◽  
Hui Yan Wang ◽  
Xiao Bing Liu

The liquid-solid two-phase turbulent flow in an axial flow pump was numerically simulated by using the SIMPLEC algorithm based Navier-Stoker and RNG k-ε turbulent model and after the secondary development of the software Fluent. The distributions of solid concentration, velocity and pressure on the impellers of the axial flow pump were analyzed at different volume concentrations at the pump inlet. The numerical results show that the head and the efficiency of the pump will reduce with the increasing of the sediment concentration in sandy rivers. This research shows that the numerical simulation results are consistent with the actual situations.


2012 ◽  
Vol 220 ◽  
pp. 7-14 ◽  
Author(s):  
V. Vidyapati ◽  
M. Kheiripour Langroudi ◽  
J. Sun ◽  
S. Sundaresan ◽  
G.I. Tardos ◽  
...  

Author(s):  
Tim Nagel ◽  
Julien Chauchat ◽  
Cyrille Bonamy ◽  
Antoine Mathieu ◽  
Xiaofeng Liu ◽  
...  

Scour around structures is a major engineering issue that requires a detailed description of the flow field as well as sediment transport processes. Due to enhanced suspended load associated with vortices generated around structures, sediment transport cannot be solely related to bed shear stress, such as Shields parameter based formula. In order to address this issue, we used a multi-dimensional two-phase flow solver, sedFoam-2.0 (Chauchat et al., GMD 2017) implemented under the open-source CFD toolbox OpenFOAM. Three configurations are studied and compared with experimental and numerical data from the literature. First, the 2D configurations of an horizontal cylinder lying on a sediment bed (Mao, 1986; Sumer et al., 2001) are investigated. Then, the 3D configuration of the scour around a vertical cylindrical pile reported by Roulund et al. (2005) for rigid-bed and live bed cases is investigated.


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