scholarly journals Numerical simulation model of vertical velocity distribution in a channel with artificial floating bed

2020 ◽  
Vol 20 (5) ◽  
pp. 1922-1932
Author(s):  
Yu Bai ◽  
Yonggang Duan ◽  
Wenjun Yue

Abstract Artificial floating bed (AFB), as a novel type of ecological drainage ditch, is extensively used worldwide. To more effectively design the structure of the project, an accurate velocity model is required. In this study, a two-dimensional Lattice Boltzmann method (LBM) was employed for the simulation of the vertical velocity in a channel with AFB. The large eddy simulation (LES) was conducted to simulate turbulent flows, while the drag force of AFB was discretized with a centered scheme. Two sets of experimental data were used to verify the model, the mean value of root mean square error (RMSE) and coefficient of determination (R2) are 0.93 and 1.84, respectively. This proved that the proposed model is more effective to simulate the vertical velocity in a channel with AFB.

2018 ◽  
Vol 28 (5) ◽  
pp. 1096-1116 ◽  
Author(s):  
Emmanuel Leveque ◽  
Hatem Touil ◽  
Satish Malik ◽  
Denis Ricot ◽  
Alois Sengissen

Purpose The Lattice Boltzmann (LB) method offers an alternative to conventional computational fluid dynamics (CFD) methods. However, its practical use for complex turbulent flows of engineering interest is still at an early stage. This paper aims to outline an LB wall-modeled large-eddy simulation (WMLES) solver. Design/methodology/approach The solver is dedicated to complex high-Reynolds flows in the context of WMLES. It relies on an improved LB scheme and can handle complex geometries on multi-resolution block structured grids. Findings Dynamic and acoustic characteristics of a turbulent airflow past a rod-airfoil tandem are examined to test the capabilities of this solver. Detailed direct comparisons are made with both experimental and numerical reference data. Originality/value This study allows assessing the potential of an LB approach for industrial CFD applications.


2005 ◽  
Vol 73 (3) ◽  
pp. 441-448 ◽  
Author(s):  
M. Yousuff Hussaini ◽  
Siva Thangam ◽  
Stephen L. Woodruff ◽  
Ye Zhou

The development of a continuous turbulence model that is suitable for representing both the subgrid scale stresses in large eddy simulation and the Reynolds stresses in the Reynolds averaged Navier-Stokes formulation is described. A recursion approach is used to bridge the length scale disparity from the cutoff wave number to those in the energy-containing range. The proposed model is analyzed in conjunction with direct numerical simulations of Kolmogorov flows.


Author(s):  
M. Yousuff Hussaini ◽  
Siva Thangam ◽  
Stephen L. Woodruff ◽  
Ye Zhou

The development of a continuous turbulence model that is suitable for representing both the subgrid scale stresses in large eddy simulation and the Reynolds stresses in the Reynolds averaged Navier-Stokes formulation is described. A recursion approach is used to bridge the length scale disparity from the cutoff wavenumber to those in the energy-containing range. The proposed model is analyzed in conjunction with direct numerical simulations of Kolmogorov flows.


Author(s):  
Iñaki Zabala ◽  
Jesús M. Blanco

The lattice Boltzmann method (LBM) is a novel approach for simulating convection-diffusion problems. It can be easily parallelized and hence can be used to simulate fluid flow in multi-core computers using parallel computing. LES (large eddy simulation) is widely used in simulating turbulent flows because of its lower computational needs compared to others such as direct numerical simulation (DNS), where the Kolmogorov scales need to be solved. The aim of this chapter consists of introducing the reader to the treatment of turbulence in fluid dynamics through an LES approach applied to LBM. This allows increasing the robustness of LBM with lower computational costs without increasing the mesh density in a prohibitive way. It is applied to a standard D2Q9 structure using a unified formulation.


Author(s):  
Michael Leschziner ◽  
Ning Li ◽  
Fabrizio Tessicini

This paper provides a discussion of several aspects of the construction of approaches that combine statistical (Reynolds-averaged Navier–Stokes, RANS) models with large eddy simulation (LES), with the objective of making LES an economically viable method for predicting complex, high Reynolds number turbulent flows. The first part provides a review of alternative approaches, highlighting their rationale and major elements. Next, two particular methods are introduced in greater detail: one based on coupling near-wall RANS models to the outer LES domain on a single contiguous mesh, and the other involving the application of the RANS and LES procedures on separate zones, the former confined to a thin near-wall layer. Examples for their performance are included for channel flow and, in the case of the zonal strategy, for three separated flows. Finally, a discussion of prospects is given, as viewed from the writer's perspective.


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