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SINGLE-RELAXATION-TIME LATTICE BOLTZMANN SIMULATION FLOW OVER A CIRCULAR CYLINDER
Rho-Taek Jung,Thel Su Su Nyein 한국해양환경·에너지학회 2017 한국해양환경공학회 학술대회논문집 Vol.2017 No.4
In this paper, the Single Relaxation Time Lattice Boltzmann Method (SRT-LBM) is applied to study. Two-Dimensional viscous flow past a circular cylinder confined in a channel has been used for simulation. Computations are carried out for different Reynolds numbers. Lattice Boltzmann equations using single relaxation times are intended to be unstable at low viscosities.
Shams Ul Islam,Raheela Manzoor,Zhou Chao Ying,Mohammad Mehdi Rashdi,A. Khan 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2
A two-dimensional numerical study is carried out to analyze the drag reduction and vortex shedding suppression behind a square cylinder in presence of splitter plate arranged in upstream, downstream and both upstream and downstream location at low Reynolds number (Re = 160). Computations are performed using a Single relaxation time lattice Boltzmann method (SRT-LBM). Firstly, the code is validated for flow past a single square cylinder. The obtained results are compared to those available in literature and found to be in good agreement. Numerical simulations are performed in the ranges of 1 ≤ L ≤ 4 and 0 ≤ g ≤ 7, where L and g are the length of splitter plate and gap spacing between the splitter plate and main square cylinder, respectively. The effect of these parameters on the vortex shedding frequency, time-trace analysis of drag and lift coefficients, power spectra analysis of lift coefficient, vorticity contours visualization and force exerted on the cylinder are quantified together with the observed flow patterns around the main cylinder and within the gap spacings. The observed results are also compared with a single square cylinder without splitter plate. We found that at some combinations of L and g, the mean drag coefficient and Strouhal number reach either its maximum or minimum value. It is found that the drag is reduced up to 62.2 %, 13.3 % and 70.2 % for upstream, downstream and dual splitter plates, respectively as compared to a single square cylinder (without splitter plate). In addition, in this paper we also discussed the applications of SRT-LBM for suppression of vortex shedding and reduction of the drag coefficients.
Safdari, A.,Kim, K.C. Pergamon Press ; Elsevier Science Ltd 2014 COMPUTERS & MATHEMATICS WITH APPLICATIONS - Vol.68 No.5
This paper reports the behavior of solid particles in a three-dimensional lid-driven cavity. The prediction of solid particle dynamics through a fluid has been an important research topic over the past few decades. Difficulties arise when trying to understand the interactions between the particle and surrounding fluid. Therefore, the Lattice Boltzmann Method (LBM) was proposed to analyze three-dimensional cubic lid-driven cavity flow at range of Reynolds numbers. The mesoscale numerical scheme of the Single Relaxation Time (SRT) lattice Boltzmann method was used to solve the equation of flow fluid. The 4th Runge-Kutta method was applied to determine the effects of the drag force on the particle, and the hard sphere model was functioned to calculate the collisions between the particle and walls. The dynamics of a solid particle using a numerical simulation of LBM showed good agreement with the established benchmark results from previous studies. In addition, the results showed that the particle trajectories are critically dependent on the magnitude of the density, diameter and vortex behavior in the cavity. Overall, the results highlight the applicability of the present method to a range of applications.
이류확산 방정식 계산을 위한 입방보간유사입자 격자볼츠만 모델
김미래,Binqi Chen,김경천 한국가시화정보학회 2022 한국가시화정보학회지 Vol.20 No.3
We propose a Cubic-Interpolated Pseudo-Particle Lattice Boltzmann method (CIP-LBM) for the convection-diffusion equation (CDE) based on the Bhatnagar-Gross-Krook (BGK) scheme equation. The CIP-LBM relies on an accurate numerical lattice equilibrium particle distribution function on the advection term and the use of a splitting technique to solve the Lattice Boltzmann equation. Different schemes of lattice spaces such as D1Q3, D2Q5, and D2Q9 have been used for simulating a variety of problems described by the CDE. All simulations were carried out using the BGK model, although another LB scheme based on a collision term like two-relation time or multi-relaxation time can be easily applied. To show quantitative agreement, the results of the proposed model are compared with an analytical solution.