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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

THERMO-QUANTUM FIELD AND SUPERTHERMO STATE

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Science in China,Ser.A 1988年第9期31卷 1104-1115页

作者：桂元星 Department of Physics dalian university of technology

On the basis of the thermo-field dynamics and the quantum field theory in curved space, a new theory of 'thermo-quantum field' (TQF) is formulated. The TQF derives the equilibrium statistical mechanics from the quantum mechanics witthout using any statistical postulate, and predicts the possible existence of a new thermal equilibrium state—superthermo state. The thermodynamic properties of the superthermo states are discussed.

关键词： quantum field thermo-field dynamics.

Finite Element Method for Design of Reinforced Concrete Offshore Platforms

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China Ocean Engineering 1992年第1期7卷 27-36页

作者： Song Yupu and Wang Jian Associate Professor, Dept. of Civil Engineering, dalian university of technology, dalian Lecturer, Dept. of Civil Engineering, dalian university of technology, dalian

A design method of reinforced concrete (R. C.) offshore platforms with nonlinear finite element analysis is proposed. According to the method, a computer program is developed. In this program nonlinear constitutive relationships and strength criteria of concrete and steel bars are included, and the progressive cracking and crushing of the concrete are taken into account. Based on the stress distribution obtained by the nonlinear finite element analysis, the amount of reinforcement in the control sections can be computed and adjusted automatically by the program to satisfy the requirement of the design. The amount of reinforcement required in the control sections, which are obtained with the nonlinear finite element analysis, is agreeable to that obtained in the experiment. This shows that the design method of R. C. offshore platform with the nonlinear finite element method proposed by the authors is reliable for practical use.

关键词： finite element method, reinforced concrete offshore platform, design method reinforcement

A　HYBRID　METHOD　FOR　THE　SIMULATION　OF　WAVE　SPECTRUM　TRANSFORMATION　AND　BREAKING　PHENOMENA　ON　A　SLOPE

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Journal of Hydrodynamics 1995年第2期7卷 76-83页

作者： Li Yu-cheng Dong Guo-hai(Department of Civil Engineering dalian university of technology,dalian 116023, P. R. China) dalian Univ of technology Dalian China

In shallow water, during the wave propagation the nonlinear and wave breaking effect must be taken into account. In this peper a simplified hybrid method was proposed, in which a combined frequency and time domain analysis was used. By using authors' method, the process are quite simple and easy to run on a PC computer, but the nonlinear and wave bleaking effect was still been considered. The computed data coincide authors' test results quite well.

关键词： wave tranformation wave breaking numerical simulstion

Mechanism of local scour around submarine pipelines based on numerical simulation of turbulence model

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Acta Oceanologica Sinica 2006年第2期25卷 142-152页

作者： L Lin1*, LI Yucheng1,3, CHEN Bing21. State Key Laboratory of Coastal and Offshore Engineering, dalian university of technology, dalian 116024, China2. School of Civil and Hydraulic Engineering, dalian university of technology, dalian 116024, China3. R&D center of civil Engineering technology, dalian university, dalian 116622, ChinaReceived 20 July 2005 accepted 14 December 2005 State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China RandD Center of Civil Engineering technology Dalian University Dalian 116622 China School of Civil and Hydraulic Engineering Dalian University of Technology Dalian 116024 China

The mechanism of local scour around submarine pipelines is studied numerically based on a renormalized group (RNG) turbulence model. To validate the numerical model, the equilibrium profiles of local scour for two cases are simulated and compared with the experimental data. It shows that the RNG turbulence model can give an appropriate prediction for the configuration of equilibrium scour hole, and it is applicable to this situation. The local scour mechanism around submarine pipelines including the flow structure, shear stress distribution and pressure field is then analyzed and compared with experiments. For further comparison and validation, especially for the flow structure, a numerical calculation employing the large eddy simulation (LES) is also conducted. The numerical results of RNG demonstrate that the critical factor governing the equilibrium profile is the seabed shear stress distribution in the case of bed load sediment transport, and the two-equation RNG turbulence model coupled with the law of wall is capable of giving a satisfying estimation for the bed shear stress. Moreover, the piping phenomena due to the great difference of pressure between the upstream and downstream parts of pipelines and the vortex structure around submarine pipelines are also simulated successfully, which are believed to be the important factor that lead to the onset of local scour.

关键词： submarine pipeline mechanism of local scour renormalized group turbulence model large eddy simulation piping

FLOW STRUCTURE AND SEDIMENT TRANSPORT WITH IMPACTS OF AQUATIC VEGETATION

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Journal of Hydrodynamics 2008年第4期20卷 461-468页

作者： LIU Cheng SHEN Yong-ming Pearl River Hydraulic Research Institute Guangzhou 510611 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China State Key L-aborat-ory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023China

Aquatic vegetation plays an important role in the flow structure of open channels and thus changes the fate and the transport of sediment. This article proposes a three-dimensional turbulence model by introducing vegetation density and drag force into the control equations of water flow in the presence of vegetation. The model was used to calculate the impacts of submerged vegetation on the vertical profiles of longitudinal flow velocities, the changes of the depth-averaged flow velocities in a compound channel with emergent vegetation in the floodplain, the removal of suspended sediment from the channels by emergent vegetation, and the bed changes around and in a vegetated island. Numerical investigations show that aquatic vegetation retards flow in the vegetation zone, reduces the sediment transport capacity, and contributes to erosion on both sides of the vegetated island. Calculated results agree well with experimental results.

关键词： three-dimensional turbulence model aquatic vegetation flow structure sediment transport suspended sediment bed surface topography change

GRAIN BOUNDARY FEATURE AND CREEP BEHAVIOR OF Fe-15Cr-25Ni ALLOYS

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Acta Metallurgica Sinica(English Letters) 1989年第5期2卷 368-373页

作者： ZHANG Junshan CHEN Weixing CAO Zhiben dalian university of technology,dalian,China Associate Professor,Department of Materials Engineering,dalian university of technology,dalian,China

Creep behavior of Fe-15Cr-25Ni alloys with different grain boundary features has been in- vestigated at 850 and 950℃ and in stress range of 14.7～78.5 *** single phase alloy exhibits typical recovery creep characteristics,and for the alloy in which M_(23)C_6 carbides densely precipitate at grain boundaries,the creep rate dramatically decreases and creep behav- ior is also significantly different from the single phase *** the carbides precipitate at grain boundaries,the dislocation density are higher and the size of subgrains near grain boundaries are smaller than those of single phase *** creep mechanisms for two grain boundary features have been discussed.

关键词： grain boundary feature recovery creep dislocation annihilation

Microstructure and Strength of Laser Welds of Sub-micron Particulate-reinforced Aluminum Matrix Composite Al_2O_(3p)/6061Al

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Rare Metals 2001年第3期20卷 178-182页

作者： Liming Liu, Jitai Niu 1) Department of Materials Engineering, dalian university of technology. dalian 116024, China 2) National Key Laboratory of Advanced Welding Production technology, Harbin Institute of technology,Harbin 150001, China 大连理工大学辽宁大连 116024 哈尔滨工业大学现代焊接生产技术国家重点实验室黑龙江哈尔滨 150001

The microstructure of laser welds of sub-micron particulate-reinforced aluminum matrix composite Al_2O_(3p)/6061Al and the weldability of the material were studied. Experimental results indicated that because of the huge specific surface area of the reinforcement, the interfacial reaction between the matrix and the reinforcement was re- strained intenslvely at elevated temperature and pulsed laser beam. The main factor affecting the weldability of the com- posite was the reinforcement segregation in the weld resulting from the push of the liquid/solid interface during the soli- dification of the molten pool. The laser pulse frequency directly affected the reinforcement segregation and the reinfor- cement distribution in the weld, so that the weldability of the composite could be improved by increasing the laser pulse frequency. On the basis of this, a satisfactory welded joint of sub-micron paniculate-reinforced aluminum matrix com- posite Al_2O_(3p)/6061Al was obtained by using appopriate welding parameters.

关键词： sub-micron particulate-reinforced aluminum matrix composite laser welding welded joint reinforced matrix

THE OPTIMIZATION OF THE HULL FORM WITH THE MINIMUM WAVE MAKING RESISTANCE BASED ON RANKINE SOURCE METHOD

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Journal of Hydrodynamics 2009年第2期21卷 277-284页

作者： ZHANG Bao-ji MA Kun JI Zhuo-shang State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian116024 China Ship CAD Engineering Center Dalian University of Technology Dalian 116024 China

The hull form optimization concerns one of the most important applications of wave making resistance theories. In order to obtain a hull form with the minimum wave making resistance, an optimization design method based on the CFD is proposed, which combines the Rankine source method with the nonlinear programming （NLP）. The bow-body shape is optimized with the minimum wave making resistance as the objective function. A hull form modification function is introduced to represent an improved hull surface, which can be used to generate a new smooth hull surface by multiplying it by the offset data of the original hull surface. The parameters of the hull form modification function are taken as the design variables. Other constraint conditions can also be considered, for example, in optimizing the lines of the bow, appropriate displacements can be taken as the basic constraints. S60 hull form is selected as the original hull. Three improved hulls are obtained by optimal design. Rankine source method proves to be an effective method in ship form optimization based on analysis of the resistance performance and lines of the improved hull.

关键词： Rankine source method CFD NLP optimization method,wave making resistance