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NUMERICAL SIMULATION OF VENTILATED CAVITATING FLOW AROUND A 2D FOIL

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Journal of Hydrodynamics 2005年第5期17卷 607-614页

作者： CHEN Xin lu chuan-jing Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China

By using a pressure-based method and the finite volume method in the framework of the time dependent Reynolds-averaged Navier-Stokes equations, the authors studied the unsteady process of ventilated cavities generated forcing air through an orifice in a 2D hydrofoil without natural cavitation physically. The computation was carried out with the Volume Of Fluid （VOF） technique to track the gas-liquid two-phase interface. The results of simulation indicate that the ventilation rate is an important parameter in determining the morphology of cavity. There exists a critical value to convert sheet cavity into supereavity. A high ventilation rate can induce a two phase interface fluctuation and enable the ventilated eavitating flow to present a characteristic of periodicity.

关键词： ventilated cavity re entrant jet interface fluctuation Volume Of Fluid (VOF) techinique

A HOMOGENOUS-EQUILIBRIUM-MODEL BASED NUMERICAL CODE FOR CAVITATION FLOWS AND EVAluATION BY COMPUTATION CASES

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Journal of Hydrodynamics 2008年第2期20卷 186-194页

作者： CHEN Ying lu chuan-jing Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China

A computer code, ELANEX, including several Homogenous-Equilibrium-Model （HEM） type cavitation models, were developed, to numerically simulate natural cavitation phenomena. The effectiveness of the code was checked by cavitation flows around the disk and cylinder body for a wide range of different cavitation numbers. Cavity profiles were compared with the analytic solution of disk and empirical formulae fitted from the experiment data, and contrast between different cavitation models were fulfilled as well. The cavity length and maximal cavity diameter were found to agree well with the analytic solutions, and detailed cavity profiles were in accordance with the experimental formula. Comparison with the hemisphere headed cylinder body presented a good agreement of the pressure coefficient with the experiment data. Reasonable drag-force coefficient variation and drag-force reduction effect were obtained.

关键词： cavitation numerical code disk hemisphere cavity profile pressure coefficient

Active stabilization methods of electric power systems with constant power loads:a review

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Journal of Modern Power Systems and Clean Energy 2014年第3期2卷 233-243页

作者： Mingfei WU Dylan Dah-chuan lu School of Electrical and Information Engineering The University of SydneyDarlingtonNSWAustralia

Modern electric power systems have increased the usage of switching power *** tightly regulated switching power converters behave as constant power loads(CPLs).They exhibit a negative incremental impedance in small signal *** negative impedance degrades the stability margin of the interaction between CPLs and their feeders,which is known as the negative impedance instability *** feeder can be an LC input filter or an upstream switching *** damping methods are preferred for the stabilization of the *** is due to their higher power efficiency over passive damping *** on different sources of damping effect,this paper summarizes and classifies existing active damping methods into three *** paper further analyzes and compares the advantages and disadvantages of each active damping method.

关键词： Stabilization LC filters Constant power loads

THE THIXOTROPY-LOOP BEHAVIORS OF AN LDPE MELT:EXPERIMENT AND SIMPLE ANALYSIS

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Journal of Hydrodynamics 2006年第6期18卷 666-675页

作者： HUANG Shu-xin lu chuan-jing Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200030 China

The time-dependent viscoelastic behaviors of an Low-Density-Pdyethyene（LDPE）（PE-FSB-23D022） melt were experimentally investigated using two types of thixotropy-loop test i.e., the triangular- and the trapezoidal-loop shear test. The shear strengthening was noted in the thixotropy-loop tests not only at high shear rate but also at low shear rate, and it was found that the dimensionless stress amplitude of shear strengthening at low shear rate is larger than that at high shear rate. Moreover, the shear strengthening is a time-dependent viscoelastic behavior that is observed during the initial stage of shearing, and it cannot be found when the time interval corresponding to the increase in shear rate is sufficiently long, The remarkable shear-weakening phenomenon was noticed at higher shear rate when shearing time is prolonged. Five types of the triangular thixotropy-loop results were marked in terms of the configurations of the stress-rate curves, which indicate the complex features of the time-dependent viscoelasticity. A simple model was used to describe the thixotropy-loop tests, and the fitted results showed good agreement with the experimental results.

关键词： thixotropy-loop test time-dependent viscoelasticity LDPE shear strengthening shear weakening

Synthesis and morphology of triangular pyramid-shaped puerarin microparticle with nanostructure

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Chinese Chemical Letters 2010年第4期21卷 484-487页

作者： lu, chuan Hua Zhang, Qun Wei Anhui Coll Tradit Chinese Med Sch Pharm Hefei 230038 Peoples R China

A type of triangular pyramid-shaped microparticles of puerarin was synthesized by using oil-in-oil microemulsion approach which is simple and economical under the action of copper *** pyramid-shaped microparticles would be made up of deposit of nanospheres or nanorods and have two significant *** is its complex surface morphology like coral *** other is a lot of nanopores in existence in the microparticle *** possible formation routes were speculated.

关键词： Triangular pyramid-shaped puerarin microparticles Synthesis Nanosphere Nanorod

MODELLING AND COMPUTATION OF UNSTEADY TURBULENT CAVITATION FLOWS

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Journal of Hydrodynamics 2006年第5期18卷 559-566页

作者： CHEN Ying lu chuan-jing WU Lei Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China

Unsteady turbulent cavitation flows in a Venturi-type section and around a NACA0012 hydrofoil were simulated by two-dimensional computations of viscous compressible turbulent flow model. The Venturi-type section flow proved numerical precision and reliability of the physical model and the code, and further the cavitation around NACA0012 foil was investigated. These flows were calculated with a code of SIMPLE-type finite volume scheme, associated with a barotropic vapor/liquid state law which strongly links density and pressure variation. To simulate turbulent flows, modified RNG k-ε model was used. Numerical results obtained in the Venturi-type flow simulated periodic shedding of sheet cavity and was compared with experiment data, and the results of the NACA0012 foil show quasi-periodic vortex cavitation phenomenon. Results obtained concerning cavity shape and unsteady behavior, void ratio, and velocity field were found in good agreement with experiment ones.

关键词： turbulent cavitation Venturi NACA0012

NUMERICAL RESEARCHES ON INTERACTION BETWEEN PROPELLERS IN UNIFORM FLOW

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Journal of Hydrodynamics 2012年第5期24卷 675-683页

作者： FENG Xue-mei lu chuan-jing WUQiong CAI Rong-quan School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 200240China Marine Design and Research Institute of China Shanghai 200011 China

Numerical simulations of the flow around two bidirectional staggered propellers are conducted in uniform flow. The computed open water performance of the fore-propeller is compared with the corresponding experimental results, and the influence of the fore-propeller on the aft one is carefully investigated. It is found that the inflow around the aft propeller close to the side of the fore is especially affected by the fore one, leading to abnormal circumferential distribution of force on the blade in the shade region. For either forces or velocity distributions, the abnormal changes behave contrarily for cases with the rotating speed larger or smaller than the idle. Moreover, the more the rotating speed of the fore differs from the idle, the larger the abnormal values become.

关键词： numerical simulation interaction propellers open water performance

Molecular Cloning and Preliminary Analysis of a Fragile Site Associated Gene

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Biomedical and Environmental Sciences 2006年第5期19卷 392-398页

作者： YI-WEN CAO chuan-lu JIANG TAO JIANG Department of Echography People＇s Armed Police General Hospital of Heilongjiang Province Harbin 150076 Heilongjiang China Department of Neurosurgery the Second Affiliated Hospital Harbin Medical University Harbin 150001 Heilongjiang China Department of Neurosurgery Neurosurgery Institute and Tiantan Hospital PUMC and CAMS Beijing 100050 China

Objective To analyze the molecular coining of a fragile site-associated gene. Methods Genomic Chinese hamster ovary （CHO） DNA library was constructed using high molecular weight CHO DNA partially digested with MboI restriction enzyme from cultured CHO cells. Screening of genomic DNA library followed the established procedures. Genomic CHO in the positive clones was sequenced. Appropriate primers were designed for the reverse transcriptase-polymerase chain reactions （RT-PCR）. The RT-PCR products were cloned into a pCRII TOPO vector and confirmed by DNA sequencing. Antibodies were prepared using synthetic peptides as antigens by immunizing the rabbits. Immunohistochemical analyses were performed to evaluate the expression of the novel gene in different tissues. Results To investigate the molecular mechanism underlying the initial events of mdrla amplification, we cloned lq31 fragile site DNA. Strikingly, we found that this fragile site contained a novel gene which was designated as a fragile site-associated （FSA） gene. FSA encoded an unusually large mRNA of - 16 kb. Full-length human FSA eDNA was cloned. FSA mRNA was expressed in many cultured cells and tissue types. Immunohistochemical analyses also revealed an expression pattern of the encoded proteins in postmitotic, well-differentiated epithelial compartments of many organs, including colon, mammary glands, ovary, prostate, and bladder. Conclusion FSA plays an important role in regulating mammalian epithelial cell growth and differentiation.

关键词： Fragile site DNA amplification Epithelial differentiation

Performance and Analysis of a Model for Describing Layered Leaf Area Index of Rice

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Agricultural Sciences in China 2011年第3期10卷 351-362页

作者： lu chuan-gen YAO Ke-min HU Ning Institute of Food Crops Jiangsu Academy of Agricultural Sciences Nanjing 210014 P.R. China College of Applied Meteorology Nanjing University of Information Science and Technology Nanjing 210044 P.R. China

Layered leaf area index （LAIk） is one of the major determinants for rice canopy. The objective of this study is to attain rice LAI k using morphological traits especially leaf traits that affected plant type. A theoretical model based on rice geometrical structure was established to describe LAI k of rice with leaf length （Li）, width （Wi）, angle （Ai）, and space （Si）, and plant pole height （H） at booting and heading stages. In correlation with traditional manual measurement, the model was performed by high R2-values （0.95-0.89, n=24） for four rice hybrids （Liangyoupeijiu, Liangyou E32, Liangyou Y06, and Shanyou 63） with various plant types and four densities （3 750, 2 812, 1 875, and 1 125 plants per 100 m2） of a particular hybrid （Liangyoupeijiu）. The analysis of leaf length, width, angle, and space on LAI k for two hybrids （Liangyoupeijiu and Shanyou 63） showed that leaves length and space exhibited greater effects on the change of rice LAI k . The radiation intensity showed a significantly negative exponential relation to the accumulation of LAI k , which agreed to the coefficient of light extinction （K）. Our results suggest that plant type regulates radiation distribution through changing LAI k . The present model would be helpful to acquire leaf distribution and judge canopy structure of rice field by computer system after a simple and less-invasive measurement of leaf length, width, angle （by photo）, and space at field with non-dilapidation of plants.

关键词： canopy structure layered leaf area index (LAI k ) model plant type rice