A nonlinear model for the subgrid timescale experienced by heavy particles in large eddy simulation of isotropic turbulence with a stochastic differential equation

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	A nonlinear model for the subgrid timescale experienced by heavy particles in large eddy simulation of isotropic turbulence with a stochastic differential equation
	Jin GD(晋国栋); He GW(何国威)
刊名	NEW JOURNAL OF PHYSICS
	2013-03-11
通讯作者邮箱	hgw@lnm.imech.ac.cn
卷号	15 期号:3 页码:035011/1-035011/27
关键词	Particle-laden turbulence Large-eddy simulation particle SGS model Langevin equation stochastic differential equation approximate deconvolution method relative dispersions
ISSN号	1367-2630
通讯作者	He GW (reprint author), Chinese Acad Sci, Inst Mech, LNM, Beijing 100190, Peoples R China
产权排序	[Jin, Guodong; He, Guo-Wei] Chinese Acad Sci, Inst Mech, LNM, Beijing 100190, Peoples R China
中文摘要	The effects of subgrid scale (SGS) motions on the dispersion of heavy particles raise a challenge to the large- eddy method of simulation (LES). As a necessary first step, we propose the use of a stochastic differential equation (SDE) to represent the SGS contributions to the relative dispersions of heavy particles in LES of isotropic turbulence. The main difficulty is in closing the SGS- SDE model whilst accounting for the effects of particle inertia, filter width and gravity. The physics of the interaction between heavy particles and SGS turbulence is explored using the filtered direct numerical simulation method. It is found in the present work that (i) the ratio of the SGS Lagrangian and Eulerian timescales is different from that of the full- scale Lagrangian and Eulerian timescales. The ratios are also dependent on filter widths. (ii) In the absence of gravity, the SGS timescale seen by heavy particles non- monotonically changes with particle Stokes number and has a maximum at particle Stokes number (St = tau(p)/delta T-E) near 0.5. (iii) In the presence of gravity, a similarity law exists between the SGS Lagrangian correlation function seen by a heavy particle within a timedelay tau and the SGS spatial correlation function with the displacement < w > tau, where < w > is the average settling velocity of a heavy particle. The joint effects of particle inertia and gravity are accounted for using the elliptic model for pair correlation of SGS velocity seen by heavy particles. The SGS timescale seen by heavy particles is extracted from the elliptic model and used to close the SGS-SDE model. The validations of the model against direct numerical simulation show that the SGS-SDE model can improve the performance of LES on relative dispersions especially when their initial separations are in the inertial subrange. Furthermore, we assess the performance of the SGS-SDE model by comparing the results with the approximate deconvolution method. The results show that the SGS-SDE model is more suitable for particles with small Stokes numbers, St(K) < 2. The model developed here provides a basis for the development of a more advanced SGS model for particles in non-homogeneous and anisotropic turbulent flows in pipes or channels.
学科主题	流体力学 ; 湍流 ; 多相流
分类号	一类
收录类别	SCI ; EI
资助信息	NSFC under grant numbers 11072247, 11021262 and 1123201, and NSAF under number U1230126.
原文出处	http://iopscience.iop.org/1367-2630/15/3/035011/ or http://dx.doi.org/10.1088/1367-2630/15/3/035011
语种	英语
WOS记录号	WOS:000316187300001
公开日期	2013-02-28
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/46894]
专题	力学研究所_非线性力学国家重点实验室
推荐引用方式 GB/T 7714	Jin GD,He GW. A nonlinear model for the subgrid timescale experienced by heavy particles in large eddy simulation of isotropic turbulence with a stochastic differential equation[J]. NEW JOURNAL OF PHYSICS,2013,15(3):035011/1-035011/27.
APA	Jin GD,&He GW.(2013).A nonlinear model for the subgrid timescale experienced by heavy particles in large eddy simulation of isotropic turbulence with a stochastic differential equation.NEW JOURNAL OF PHYSICS,15(3),035011/1-035011/27.
MLA	Jin GD,et al."A nonlinear model for the subgrid timescale experienced by heavy particles in large eddy simulation of isotropic turbulence with a stochastic differential equation".NEW JOURNAL OF PHYSICS 15.3(2013):035011/1-035011/27.