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Applied Mathematics and Mechanics(English Edition) 2019年第3期40卷 305-320页

作者： Beiji SHI Xiaolei YANG Guodong JIN Guowei HE Shizhao WANG The State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences School of Engineering Sciences University of Chinese Academy of Sciences Department of Civil Engineering College of Engineering and Applied Sciences Stony Brook University

A novel method is proposed to combine the wall-modeled large-eddy simulation(LES) with the diffuse-interface direct-forcing immersed boundary(IB) method.The new developments in this method include:(i) the momentum equation is integrated along the wall-normal direction to link the tangential component of the effective body force for the IB method to the wall shear stress predicted by the wall model;(ii) a set of Lagrangian points near the wall are introduced to compute the normal component of the effective body force for the IB method by reconstructing the normal component of the velocity. This novel method will be a classical direct-forcing IB method if the grid is fine enough to resolve the flow near the wall. The method is used to simulate the flows around the DARPA SUBOFF model. The results obtained are well comparable to the measured experimental data and wall-resolved LES results.

关键词： wall model large-eddy simulation(LES) immersed boundary(IB)method diffuse-interface

Turbulent Inlet Conditions Modeling using large-eddy Simulations

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Computer Modeling in Engineering & Sciences 2015年第2期104卷 105-132页

作者： M.M.R.Damasceno J.M.Vedovoto A.da Silveira-Neto UFU UberlandiaMGBrazil

Turbulence is a phenomenon which presents peculiarities when it is experimented or simulated.This occurs due to its complexity and high sensibility to the inlet conditions of the turbulent flow fields,as well as the presence of a large range of time and length scales.A simplification for this situation is obtained with the use of approximations and turbulence models.In the present work,the largeeddy Simulations methodology was applied,aiming the modeling of the previously mentioned complexity,which consists in using a filter to resolve the large scales while the remaining scales were determined by classical and dynamic Smagorinsky models.Three different approximations for the inlet conditions were applied:white noise,Random Flow Generation(RFG)and Synthetic eddy Method(SEM).It was possible to realize that the use of the dynamic Smagorinky model and the RFG or SEM methodologies resulted in a better characterization of the studied flow.

关键词： turbulent inlet conditions turbulence models large-eddy simulations

large-eddy simulations and vortex structures of turbulent jets in crossflow

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Science China(Physics,Mechanics & Astronomy) 2007年第1期50卷 118-132页

作者： GUAN Hui1,2 & WU ChuiJie2 1 School of Mechanical and Power Engineering,East China University of Science and Technology,Shanghai 200237,China 2 Research Center for Fluid Dynamics,PLA University of Science and Technology,Nanjing 211101,China School of Mechanical and Power Engineering East China University of Science and Technology Shanghai China Research Center for Fluid Dynamics PLA University of Science and Technology Nanjing China

Using the method of large-eddy simulation, the 3-dimensional turbulent jets in crossflow with stream-wise and transverse arrangements of nozzle are simulated, emphasizing on the dynamical process of generation and evolution of vortex structures in these flows. The results show that the basic vortex structures in literatures, such as the counter-rotating vortex pair, leading-edge vortices, lee-side vortices, hanging vortices, kidney vortices and anti-kidney vortices, are not independent physical substances, but local structures of the basic vortex structure of turbulent jets in crossflow-the 3-D stretching vortex rings originating from the orifice of the nozzle, which is discovered in this study. Therefore, the most important large-scale structures of turbulent jets in crossflow are unified to the 3-D vortex rings which stretch and twist in stream-wise and swing in transverse directions. We also found that the shedding frequencies of vortex rings are much lower than the one corresponding to the appearance of leading-edge and lee-side vortices in the turbulent jets.

关键词： turbulent jet in crossflow coherent structure large-eddy simulation

large-eddy simulation of formation of three-dimensional aeolian sand ripples in a turbulent field

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Science China(Physics,Mechanics & Astronomy) 2008年第8期51卷 945-960页

作者： WU ChuiJie1,WANG Ming2 & WANG Liang3 1 State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,China 2 Yellow River Institute of Hydraulic Research,Zhengzhou 450003,China 3 Research Center for Fluid Dynamics,Science School,PLA University of Science and Technology,Nanjing 211101,China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian China Yellow River Institute of Hydraulic Research Zhengzhou China Research Center for Fluid Dynamics Science School PLA University of Science and Technology Nanjing China

With the method of large-eddy simulation,the equation of spherule motion and the method of immersed boundary condition,numerical simulations of three-dimen-sional turbulent aeolian motion and the formation of sand ripples under three-di-mensional turbulent wind and the mutual actions of saltation and creeping motion were carried out. The resulting sand ripples have the form that is flat on the upwind side and steep on the leeward,which is identical to the sand ripples in nature. We also realized the self-restoration process of three-dimensional sand ripples,which shows the correctness of the method of numerical simulation and the models of saltation and creeping. Finally,We analyzed the influence of sand ripples on the three-dimensional turbulent wind field,and found that due to the appearance and development of sand ripples,in the normal direction of ground there exists stronger energy exchange,and moreover,there is close correspondence between the forms of sand ripples and the vorticity close to the ground surface.

关键词： large-eddy simulation equation of spherule motion sand ripples saltation creep

Development of SOM combustion model for Reynolds-averaged and large-eddy simulation of turbulent combustion and its validation by DNS

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Science China(Technological Sciences) 2008年第8期51卷 1073-1086页

作者： ZHOU LiXing Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China Department of Engineering Mechanics Tsinghua University Beijing China

The derivation and closure methods of the second-order moment (SOM) combus- tion model are proposed. The application of this model to Reynolds averaged (RANS) and large-eddy simulation (LES) of turbulent swirling diffusion combustion, jet diffusion combustion, and bluff-body stabilized premixed combustion is sum- marized. It is indicated that the SOM model is much better than the eddy-beak-up (EBU) and presumed PDF models widely used in commercial software and engi- neering. The SOM modeling results are close to those obtained using the most accurate but much more complex PDF equation model. Moreover, it can save much more computation time than the PDF equation model. Finally, the SOM model is validated by the direct numerical simulation (DNS) of turbulent reacting channel flows.

关键词： turbulent combustion second-order moment model Reynolds averaged simulation large-eddy simulation

large-eddy simulations of the Richtmyer-Meshkov instability of rectangular interfaces accelerated by shock waves

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Science China(Physics,Mechanics & Astronomy) 2010年第5期53卷 905-914页

作者： WANG Tao,BAI JingSong,LI Ping & LIU Kun Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621900,China Institute of Fluid Physics China Academy of Engineering Physics Mianyang China

A parallel algorithm and code MVFT(multi-viscous-fluid and turbulence) of large-eddy simulation(LES) is developed from our MVPPM(multi-viscous-fluid piecewise parabolic method),and performed to solve the multi compressible Navier-Stokes(N-S) equations.The effect of the unresolved subgrid-scale(SGS) motions on the large scales is represented by different SGS stress models in LES.A Richtmyer-Meshkov instability experiment of the evolution of a rectangular block of SF6,which occupies half of the height of the shock tube test section,following the interaction with a planar shock wave,is numerically and exhaustively simulated by this code.The comparison between experimental and simulated images of the evolving SF6 block shows that they are consistent.The numerical simulations reproduce the complex developing process of SF6 block,which grows overturningly.The geometric quantities that characterize the extents of SF6 block are also compared in detail between numerical simulations and experiment with good agreements between them,a quantitative demonstration of the developing law of SF6 block.There is an evident discrepancy between the three numerical simulations for the maximum position of the right edge of block at the late stage,because the right interface grows complicated and the dissipation is different for different SGS models.The SGS turbulent dissipation,molecular viscosity dissipation and SGS turbulent kinetic energy have been studied and analyzed.They have a similar distribution to the large eddy structures.The SGS turbulent dissipation is much greater than the molecular viscosity dissipation;the SGS turbulent dissipation of Vreman model is smaller than the Smagorinsky model.In general,the simulated results of Vreman SGS model are better compared with the dynamic viscosity and Smagorinsky SGS model.The vorticity and circulation deposition on the block interface have also been investigated.

关键词： large-eddy simulation Navier-Stokes equations subgrid-scale Richtmyer-Meshkov instability turbulent dissipation turbulent kinetic energy circulation deposition

large-eddy Simulations of turbulent flows with lattice Boltzmann dynamics and dynamical system sub-grid models

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Science China(Technological Sciences) 2009年第3期52卷 670-679页

作者： GUAN Hui1 & WU ChuiJie2 1 Research Center for Fluid Dynamics, PLA University of Science and Technology, Nanjing 211101, China 2 School of Aeronautics and Astronautics, Dalian University of Technology, Dalian 116024, China Research Center for Fluid Dynamics PLA University of Science and Technology Nanjing China School of Aeronautics and Astronautics Dalian University of Technology Dalian China

In this paper, two sub-grid scale (SGS) models are introduced into the Lattice Boltzmann Method (LBM), i.e., the dynamics SGS model and the dynamical system SGS model, and applied to numerically solving three-dimensional high Re turbulent cavity flows. Results are compared with those obtained from the Smagorinsky model and direct numerical simulation for the same cases. It is shown that the method with LBM dynamics SGS model has advantages of fast computation speed, suitable to simulate high Re turbulent flows. In addition, it can capture detailed fine structures of turbulent flow fields. The method with LBM dynamical system SGS model dose not contain any adjustable parameters, and can be used in simulations of various complicated turbulent flows to obtain correct information of sub-grid flow field, such as the backscatter of energy transportation between large and small scales. A new average method of eliminating the inherent unphysical oscillation of LBM is also given in the paper.

关键词： large-eddy Simulation Lattice Boltzmann Method dynamics sub-grid scale model dynamical system sub-grid scale model parallel computation

A new numerical framework for large-eddy simulation of waves generated by objects piercing water surface

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Theoretical & Applied Mechanics Letters 2019年第2期9卷 79-83页

作者： Zixuan Yang Zuo Cui Shizhao Wang The State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences School of Engineering Sciences University of Chinese Academy of Sciences School of Aerospace Engineering Guizhou Institute of Technology

A novel numerical framework is developed for large-eddy simulation(LES) of interactions among air, water, and solid bodies. The motions of air and water are solved on a fixed block-structured mesh, with the air–water interface captured using the volume-of-fluid method. A new sub-grid scale stress model based on the vortex identifier is used to improve the robustness and efficiency of the simulation flows with air–water interface. The new framework is tested in the context of bow waves and Kelvin waves generated by a water-surface vehicle. Wave breaking at the bow of the vehicle is captured in LES. The LES results of wave geometry approaches the measurements progressively as the grid resolution is refined. The simulation results indicate that LES is a useful tool for studying wave dynamics of water-surface vehicles.

关键词： large-eddy simulation Wave breaking Wave-structure interactions

Temporal large-eddy Simulations of the Near-Field of an Aircraft Wake

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Open Journal of Fluid Dynamics 2018年第2期8卷 161-180页

作者： Roberto Paoli Henri Moet Department of Mechanical and Industrial Engineering University of Illinois at Chicago Chicago IL USA Argonne National Laboratory Computational Science Division Argonne IL USA European Center for Research and Advanced Training in Scientific Computation Toulouse France

The near-field dynamics of an aircraft wake is studied by means of temporal large-eddy simulations, with and without considering the effect of engine jets. In the absence of jets, the simulations showed the roll-up of the initial vorticity sheet shed by the wing and the occurrence of short-wavelength instability in a pair of primary co-rotating vortices. The main consequence of the instability is the modification of the internal structure of the vortex, compared to the two-dimensional stable behavior. The presence of engine jets affects the roll-up of the vorticity sheet and causes an enlargement of the final merged vortex core compared to the case without jets.

关键词： Aircraft Wake Vortices large-eddy Simulation Wake Turbulence

Applying resolved-scale linearly forced isotropic turbulence in rational subgrid-scale modeling

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Acta Mechanica Sinica 2019年第3期35卷 486-494页

作者： Chuhan Wang Mingwei Ge School of Renewable Energy North China Electric Power UniversityBeijing 102206China LMP Ecole Centrale de PékinBeihang UniversityBeijing 100191China

In previous attempts of rational subgrid-scale (SGS) modeling by employing the Kolmogorov equation of filtered (KEF) quantities, it was necessary to assume that the resolved-scale second-order structure function is stationary. Forced isotropic turbulence is often used as a framework for establishing and validating such SGS models based on stationary restrictions, for it generates statistical stationary samples. However, traditional forcing method at low wavenumbers cannot provide an analytic form of forcing term for a complete KEF in physical space, which has been illustrated to be essential in the modeling of such SGS models. Thus, an alternative forcing method giving an analytic forcing term in physical space is needed for rational SGS modeling. Giving an analytic linear driving term in physical space, linearly forced isotropic turbulence should be considered an ideal theoretical framework for rational SGS modeling. In this paper, we demonstrate the feasibility of establishing a rational SGS model with stationary restriction based on linearly forced isotropic turbulence. The performance of this rational SGS model is validated. We, therefore, propose the use of linearly forced isotropic turbulence as a complement to free-decaying isotropic turbulence and low-wavenumber forced isotropic turbulence for SGS model validations.

关键词： Homogeneous isotropic turbulence large-eddy simulation Subgrid-scale model Forced turbulence