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PARTIALLY AVERAGED NAVIER-STOKES METHOD FOR TIME-DEPENDENT TURBULENT CAVITATING FLOWS

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Journal of Hydrodynamics 2011年第1期23卷 26-33页

作者： HUANG Biao wang guo-yu School of Vehicle and Transportation Engineering Beijing Institute of Technology Beijing 100081 China

Cavitation typically occurs when the fluid pressure is lower than the vapor pressure in a local thermodynamic state,and the flow is frequently unsteady and *** Reynolds-Averaged Navier-Stokes（RANS）approach has been popular for turbulent flow *** most widely used ones,such as the standard k-εmodel,have well-recognized deficiencies when treating time dependent flow *** identify ways to improve the predictive capability of the current RANS-based engineering turbulence closures,conditional averaging is adopted for the Navier-Stokes equation,and one more parameter,based on the filter size,is introduced into the k-ε*** the Partially Averaged Navier-Stokes（PANS）model,the filter width is mainly controlled by the ratio of unresolved-to-total kinetic *** model is assessed in unsteady cavitating flows over a Clark-Y *** the experimental validations regarding the forces,frequencies,cavity visualizations and velocity distributions,the PANS model is shown to improve the predictive capability considerably,in comparison to the standard k-ε model,and also,it is observed the value of1f in the PANS model has substantial influence on the predicting *** the filter width1f is decreased,the PANS model can effectively reduce the eddy viscosity near the closure region which can significantly influence the capture of the detach cavity,and this model can reproduce the time-averaged velocity quantitatively around the hydrofoil.

关键词： cavitating flow PANS model filter width unresolved-to-total kinetic energy

Evaluation of a Filter-Based Model for Computations of Cavitating Flows

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Chinese Physics Letters 2011年第2期28卷 172-175页

作者： HUANG Biao wang guo-yu School of Mechanical and Vehicular Engineering Beijing Institute of TechnologyBeijing 100081

To identify ways to improve the predictive capability of the current RANS-based cavitating turbulent closure,a filter-based model(FBM)is introduced by considering sub-filter *** sub-filter stress is constructed directly by using the filter size and the conventional turbulence *** model is evaluated in steady cavitating flow over a blunt body revolution and unsteady cavitating flow around a Clark-Y hydrofoil *** with the experimental data,those results indicate that FBM can be used to improve the predictive capability considerably.

关键词： closure unsteady turbulence

THREE-DIMENSIONAL NUMERICAL SIMULATION OF WAVE SLAMMING ON AN OPEN STRUCTURE

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Journal of Hydrodynamics 2012年第4期24卷 526-534页

作者： DING Zhao-qiang wang guo-yu REN Bing State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

The three-dimensional numerical simulation of wave slamming on an open structure in the splash zone is carried out based upon the Volume Of Fluid （VOF） method. A wave basin is established by solving the continuity equation and the Navier-Stoke equations. The linear wave-maker is placed on the left side of the basin, and the numerical sponge layer and the SRC are placed on the right side of the basin to damp the incident waves. The three-dimensional wave slamming boundary condition is adopted to model waves in contact with and separated from the underside of the structure. The numerical results of wave slamming on a foursquare structure for various parametric cases are verified by the experimental results. Meanwhile, the characteristics of the wave impact forces on the undersides of the rectangular structures with various length-breadth ratios are discussed.

关键词： wave slamming three-dimensional Volume Of Fluid (VOF)

Shape Descriptor with Morphology Method for Color-based Tracking

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International Journal of Automation and computing 2007年第1期4卷 101-108页

作者： Na wang guo-yu wang Information Science and Engineering School Ocean University of China Qingdao 266071 Shandong PRC

Tracking images using shape descriptor can be more accurate than using other existing methods and it is most useful when the environment is complex. However the existing methods with shape descriptor get more labeled parts to compare and detect the object in an image, which makes the computation more complicated. Thus, we need a trade-off between the accuracy and efficiency requirements. This paper aims to bridge this gap between the accuracy and efficiency requirements by using morphology method. To improve the original monochromatic object detecting system, we propose a new color descriptor to preprocess the image with polychromatic object. Experiments have been conducted and shown the proposed method has made a great improvement in the time complexity minimization comparing with the performances of the original detection algorithm.

关键词： Shape descriptor color descriptor morphology image tracking.

NUMERICAL SIMULATION OF HYDRODYNAMIC CHARACTERISTICS ON AN ARC CROWN WALL USING VOLUME OF FLUID METHOD BASED ON BFC

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Journal of Hydrodynamics 2011年第6期23卷 767-776页

作者： LI Xue-yan REN Bing wang guo yu wang Yong-xue State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023China

In the present study, a new algorithm based on the Volume Of Fluid （VOF） method is developed to simulate the hydrodynamic characteristics on an arc crown wall. Structured grids are generated by the coordinate transform method in an arbitrary complex region. The Navier-Stokes equations for two-dimensional incompressible viscous flows are discretized in the Body Fitted Coordinate （BFC） system. The transformed SIMPLE algorithm is proposed to modify the pressure-velocity field and a transformed VOF method is used to trace the free surface. Hydrodynamic characteristics on an arc crown wall are obtained by the improved numerical model based on the BFC system （BFC model）. The velocity field, the pressure field and the time profiles of the water surface near the arc crown wall obtained by using the BFC model and the Cartesian model are compared. The BFC model is verified by experimental results.

关键词： Body Fitted Coordinate (BFC) SIMPLE scheme Volume Of Fluid (VOF) method arc crown wall staggered grid

Crack Properties of Lean Duplex Stainless Steel 2101 in Hot Forming Processes

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Journal of Iron and Steel Research International 2011年第4期18卷 58-62页

作者： FANG Yi-liu LIU Zhen-yu wang guo-dong State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

The crack behavior of LDX 2101 by hot compression tests in the temperature range of 950 to 1150 ℃ and strain rate range of 0.01 to 30 s-1 was *** hot workability map of LDX 2101 was constructed and the alloy exhibited a better crack resistance at higher temperature and lower strain *** initiated and coalesced into crack at subsurface on the equatorial plane of bulge surface under secondary tensile *** cracks were orientated at an angle of approximately 45° with respect to the compression axis due to the secondary tensile *** easily initiated on the interface of ferrite and austenite and propagated within *** predicted results using specific plastic work approach were matched well with the free surface cracks.

关键词： lean duplex stainless steel hot workability crack specific plastic work approach

Green and controllable metal-free nitrification and nitration of arylboronic acids

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Chinese Chemical Letters 2012年第6期23卷 643-646页

作者： Shuai wang Chun Chun Shu Tao wang Jian yu guo Bing Yan Department of Chemistry Lishui University Lishui 32300 China

A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids, which can be controlled by the reaction conditions. The process provides an attractive alternative to th... 详细信息

关键词： Nitrification Nitration Arylboronic acids

Surface modification of polyester film by glow discharge tunnel at atmospheric pressure

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 459-462页

作者： XU Xiang-yu wang Shou-guo YE Tian-chun JING Guang-yin yu Da-peng State Key Laboratory for Mesoscopic Physics School of Physics Beijing 100871 China The Institution of Microelectronics Chinese Academy of Sciences Beijing 100010 China The Institution of Microelectronics Chinese Academy of Sciences Beijing 100010 China The Institution of Microelectronics Chinese Academy of Sciences Beijing 100010 China State Key Laboratory for Mesoscopic Physics School of Physics Beijing 100871 China State Key Laboratory for Mesoscopic Physics School of Physics Beijing 100871 China

A large-area improved dielectric barrier glow discharge tunnel has been developed for modifying the surface of polyester film at atmospheric pressure with argon and oxygen gas mixtures. The electrical properties of the glow discharge tunnel were studied by simultaneous measurement of the voltage and current. In addition, the effect of the glow discharge tunnel treatment on the surface of polyester film were studied. The resultant modifications of the surface properties of the treated samples were investigated through scanning probe microscopy and contact angle measurement.

关键词： glow discharge tunnel electrical characteristics surface modification polyester film

Development of Ti-Microalloyed 600 MPa Hot Rolled High Strength Steel

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Journal of Iron and Steel Research International 2010年第12期17卷 54-58,64页

作者： YI Hai-long LIU Zhen-yu wang guo-dong WU Di State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

A high strength steel with yield strength on the order of 600 MPa was developed successfully with only addition of titanium alloying element based on a low-carbon steel. The results showed that the hot deformation accelerated ferrite and pearlite transformation and retarded bainite transformation under continuous cooling condition. The microstructure of this steel was mainly composed of fine grained ferrite and carbides distributing along the ferrite grain boundaries. The yield and tensile strengths of steels were about 620--650 MPa and 720--740 MPa, respectively, and the values of strain hardening exponent and plastic strain ratio were 0.12 and 0.80, respectively, thereby providing a good combination of strength with toughness. In short, the fine grained ferrite and TiC precipitation strengthening contributed to a high strength.

关键词： hot rolled high strength steel TMCP (thermomechanical control process) precipitate carbide