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Phase difference effect on collective locomotion of two tandem autopropelled flapping foils

Physical Review Fluids 2019年第5期4卷 054101-054101页

作者： Xingjian Lin Jie Wu Tongwei Zhang Liming Yang Department of Aerodynamics Nanjing University of Aeronautics and Astronautics Yudao Street 29 Nanjing Jiangsu 210016 China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information Technology Nanjing University of Aeronautics and Astronautics Yudao Street 29 Nanjing Jiangsu 210016 China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Yudao Street 29 Nanjing Jiangsu 210016 China Department of Mechanical Engineering National University of Singapore 10 Kent Ridge Crescent Singapore 119260

The effect of phase difference on the collective locomotion of two tandem flapping foils is numerically studied in this paper. The numerical results indicate that the collective locomotion is greatly affected by the phase difference. Two distinct collective modes are observed, i.e., the fast mode and the slow mode. The fast mode is only observed in part of the range of the phase difference (ϕ), i.e., ϕ=0.0−0.1π and 1.5π–1.9π with appropriate initial distance, and the slow mode appears in the range of ϕ=0.3π−1.4π. Meanwhile, the follower of the two foils has hydrodynamic benefit in both fast and slow modes, and it can obtain the highest efficiency in the fast mode at ϕ=1.6π. However, the leader can only achieve hydrodynamic benefit in the fast mode, and the highest efficiency occurs at ϕ=0.1π. In addition, the stable distance between two foils in the slow mode can be quantized with the phase difference. Furthermore, the fluid-structure interactions between two foils are also analyzed. Two distinct vortex interactions are observed in the fast mode, i.e., merging interaction and broken interaction, which, respectively, result in the highest propulsive efficiency for the follower and the leader. In the merging interaction, the leading edge vortex of the leader is captured by the follower, which results in the weak trailing edge vortex of the leader but a strong trailing edge vortex of the follower. In the broken interaction, the leading edge vortex of the follower sheds into the wake together with the trailing edge vortex of the leader, and induces the trailing edge vortex of the follower to be broken into two parts. Which kind of vortex interaction occurs depends on the phase difference. The results obtained here may provide some light on understanding the coordinated behavior of biological collectives.

关键词： Locomotion Immersed boundary methods Navier-Stokes equation

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Optimal design of guide vane inthe cyclone vortex finder based on orthogonal analysis 12

Optimal design of guide vane inthe cyclone vortex finder bas...

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12th International Conference on Fluidized Bed Technology, CFB 2017

作者： Huang, Zhong Liu, Ming Liu, Guanjie Wang, Fengyang Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering Xi 'an Jiaotong University Xi 'an710049 China State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing100084 China China Huaneng Clean Energy Research Institute Beiijing102209 China

A new structure of installing guide vane inside eccentric vortex finder of cyclone was proposed. Five parameters including eccentric ratio e, blade number Z, hub inlet installing angle p, middle coefficient of hub installing angle k, shroud inlet installing angle increment Ap were selected to design an orthogonal table of five elements and four levels. Based on RNG k-e model, separation efficiencies of the conventional cyclone and 16 cyclones installing guide vanes inside vortex finder were calculated. By means of orthogonal analysis, the influence of each element has been ranked, and the optimal level of each element has been combined as the optimal structure. The simulation result indicated that the separation efficiency of the optimal structure has increased up to 7.04% while the pressure drop decreased no more than 12.5%. The flow field analysis showed the velocity in the inner vortex of cyclone was lower, while it was higher in the outer vortex, which is of great help for particle separation.

关键词： Vortex flow

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Sand particle lift-off velocity measurements and numerical simulation of mass flux distributions in a wind tunnel

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Journal of Arid Land 2017年第3期9卷 331-344页

作者： XIAO Fengjun DONG Zhibao GUO Liejin WANG Yueshe LI Debiao National Demonstration Center for Experimental Geography Education College of Tourism and Environment Shaanxi Normal University Xi'an 710119 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Xi'an Special Equipment Inspection Institute Xi'an 710065 China

Lift-off velocity of saltating sand particles in wind-blown sand located at 1.0 mm above the sand bed surface was measured using a phase Doppler particle analyzer in a wind tunnel. The results show that the probability distribution of lift-off velocity can be expressed as a lognormal function, while that of lift-off angle follows an exponential function. The probability distribution of lift-off angle conditioned for each lift-off velocity also follows an exponential function, with a slope that becomes steeper with increasing lift-off velocity. This implies that the probability distribution of lift-off velocity is strongly dependent on the lift-off angle. However, these lift-off parameters are generally treated as an independent joint probability distribution in the literature. Numerical simulations were carried out to investigate the effects of conditional versus independent joint probability distributions on the vertical sand mass flux distribution. The simulation results derived from the conditional joint probability distribution agree much better with experimental data than those from the independent ones. Thus, it is better to describe the lift-off velocity of saltating sand particles using the conditional joint probability distribution. These results improve our understanding of saltation processes in wind-blown sand.

关键词： lift-off velocity lift-off angle joint probability distribution sand mass flux saltation

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Sa2045 MAGNETIC ANCHORING ASSISTED ENDOSCOPIC IRREVERSIBLE ELECTROPORATION FOR GASTRIC MUCOSAL ABLATION: A PRECLINICAL FEASIBILITY STUDY IN CANINE MODEL

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Gastrointestinal Endoscopy 2020年第6期91卷 AB257-AB257页

作者： Fenggang Ren Qingshan Li Xuyao Gao Yuchi Zhang Jing Zhang Zhuoqun Li Dake Chu Zheng Wu Rongqian Wu Yi Lv National Local Joint Engineering Research Center for Precision Surgery and Regenerative Medicine First Affiliated Hospital of Xi’an Jiaotong University Xi'an China Department of Hepatobiliary Surgery First Affiliated Hospital of Xi’an Jiaotong University Xi'an China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China Department of Gastroenterology First Affiliated Hospital of Xi’an Jiaotong University Xi'an China

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Rapid and productive extraction of high purity cellulose material via selective depolymerization of the lignin-carbohydrate complex at mild conditions

Rapid and productive extraction of high purity cellulose mat...

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中国化学会第十九届全国化学热力学和热分析学术会议

作者： Jiming Yang Xingmei Lu Xiaomin Liu Junli Xu Qing Zhou Suojiang Zhang Beijing Key Laboratory of Ionic Liquids Clean Process Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of Sciences College of Chemistry and Chemical Engineering University of Chinese Academy of Sciences

The ILs are effective solvent to dissolve cellulose,however there were much room to improve in the pretreatment of lignocellulose using pure *** this work,an new green cellulose extraction method – the selective degradation dissolution extraction(SDDE) method based on the [Bmim]Cl–AS(*** sulfonic acid(AS)) solvent system – was found which could rapidly extract a high yield and purity of cellulose from cornstalk at relatively low temperatures in a remarkably short *** the SDDE method,the lignin-carbohydrate complex protective layer(LCCPL),which wraps around the cellulose,was selectively depolymerized into small molecules;as a result,the rapid dissolution of lignocellulose biomass and the efficient removal of lignin and hemicellulose from the regenerated material(RM) were successfully *** cellulose content of the RM could reach 99.16 ± 0.15%,which is the highest purity of cellulose extracted from the lignocellulose biomass in one step by IL solvent *** delignification rate could reach 97.56 ± 0.29% while the hemicellulose was completely removed in only 1 h after the cornstalk powder was dissolved in [Bmim]Cl–AS(the AS content was 1.5 wt%) at 100 °*** the mild fractionation conditions reduced consumption of energy greatly as well as that the additive was cheap and environmentally friendly,the SDDE might be able to provide a feasible path to achieve an efficient cellulose extraction from lignocellulose *** addition,utilization of the lignocellulose biomass mostly focused on the preparation of bioethanol via hydrolysis and *** work provided an alternative that high purity cellulose derivatives and cellulose composites could be produced from the lignocellulose biomass.

关键词： Ionic liquids amino sulfonic acid cornstalk depolymerization

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Study of an inter-wrapper flow model and effects in sodium-cooled fast reactor

Study of an inter-wrapper flow model and effects in sodium-c...

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2017 Transactions of the American Nuclear Society, ANS 2017

作者： Zhang, Dalin Song, Ping Wang, Shibao Wang, Xin'an Chen, Jing Yue, Nina Tian, Wenxi Qiu, Suizheng Su, G.H. School of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University No.28 Xianning West Road Xi'an710049 China

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Experimental study on pressure drop characteristic of wet air with ash particles in a horizontal tube bundle heat exchanger

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Energy Procedia 2017年 142卷 4010-4015页

作者： Yuanzhi Qin Jingying Yang Haibo Dai Jinshi Wang Ming Liu Junjie Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

The pressure drop characteristic of wet air with ash particles in a horizontal tube bundle heat exchanger was studied experimentally. The variations with time, effects of water vapor mass fractions and mainstream velocities on pressure drop characteristic were presented. Experimentally results showed that with the increase in the time, the pressure drop coefficient firstly increased then became stable. In the case of wet air with ash particles, the pressure drop coefficient increased with the increase of the water mass fraction and decreased with the increase of the mainstream velocity. Compared with wet air without ash particles, the pressure drop coefficients were higher in the presence of ash particles, due to ash deposition.

关键词： Pressure drop coefficient Heat exchanger wet air Ash particles

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Chaotic Characteristics Analysis on Recognition of Steam Plume flow Pattern of Direct Contact Condensation in a Rectangular Channel

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Energy Procedia 2017年 142卷 3827-3832页

作者： Binbin Qiu Jia Liu Jiping Liu Junjie Yan Xiaoping Yang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

Chaotic characteristics of direct contact condensation(DCC) for steam jet in subcooled water in a rectangular channel were analyzed at subcooled water temperature of 30 ℃. The steam mass flux and Reynolds number of subcooled water were in the range of 250-600kg/(m 2 s) and 78,000-172,000 respectively. Three different flow patterns, bubble flow, oscillation jet and stable jet, were observed. Correlation dimension( D 2 ) changes with flow patterns. For bubble flow, oscillation jet and stable jet, the corresponding correlation dimension values increase and are in the ranges of 9.68~10.30, 10.03~11.17 and 11.10~12.62, respectively. Different flow patterns have different Hurst exponent( H ). From the range of correlation dimensions and Hurst exponents, the flow pattern of steam jet can be recognized without looking the picture of steam plume. This result is very important for flow pattern recognition without the observation windows.

关键词： flow pattern recognition chaotic characteristics correlation dimension Hurst exponent

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精准医学智能决策支持系统PreMedKB的构建与临床应用（英文）

精准医学智能决策支持系统PreMedKB的构建与临床应用（英文）

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2019中国化学会第十五届全国计算（机）化学学术会议

作者：郁颖 Jingcheng Yang Yunjin Wang Zipeng Lin Zhaojie Xia Xiangyu Zhang Kailiang Jin Yuanting Zheng Li Guo Leming Shi 复旦大学 State Key Laboratory of Genetic Engineering School of Life Sciences and Shanghai Cancer Hospital/Cancer Institute Fudan University State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences *** Co. Ltd.

One important aspect of precision medicine aims to deliver the right medicine to the right patient at the right dose at the right time based on the unique ‘omics' features of each individual patient, thus maximizing drug efficacy and minimizing adverse drug reactions. However, fragmentation and heterogeneity of available data makes it challenging to readily obtain first-hand information regarding some particular diseases, drugs, genes and variants of interest. Furthermore, facing a large number of variants derived from the sequencing analysis results of different patients, there is an urgent need for an infrastructure to perform simple, quick, and routine annotations of multi-dimensional data. Therefore, we developed an intelligent decision-making system for precision medicine, including a Precision Medicine Knowledgebase(PreMedKB) and a Personal Genome Interpreter(PGI). PreMedKB was built by seamlessly integrating the four fundamental components of precision medicine: diseases, genes, variants and drugs. PreMedKB allows for search of comprehensive information within each of the four components, and the relationships between any two or more components. PreMedKB is an efficient and user-friendly tool to assist researchers, clinicians or patients in interpreting a patient's genetic profile in terms of discovering potential pathogenic variants, recommending therapeutic regimens, designing panels for genetic testing kits, and matching patients for clinical trials. Pre Med KB is freely accessible and available at http://***/premedkb/***#/home[1]. Based on the knowledgebase of PreMedKB, PGI was then developed by integrating genomic variants, clinical information and disease-specific knowledge for drug recommendation. It is used for intelligently interpreting clinical meanings of a cancer patient's genetic variants in terms of disease diagnosis, prognosis, treatment selection and pathogenicity. The intelligent decision-making system for precision medic

关键词： Precision medicine knowledgebase genomic decision-making system

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Microstructure evolution and properties evaluation of a novel bondline based on Cu@Sn Preform during temperature treatment

Microstructure evolution and properties evaluation of a nove...

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第十九届国际电子封装技术会议(ICEPT 2018)

作者： Hongyan xu Ju Xu Puqi Ning Jianqiang Li Beijing Engineering Laboratory of Electrical Drive System & Power Electronic Device Packaging Techno State Key Laboratory of Multiphase Complex System Institute of Process EngineeringChinese Academy o

The microstructure and properties of Cu@Cu3Sn@Cu6Sn5three-dimensional network bonding interconnections based on Cu@Sn preform was *** through holes were observed at the bulk in as-reflowed,aged and temperature cycling *** evolution and phase transformation during thermal treatment test were studied,the shear strength of three-dimensional network bondlines for as-reflowed and thermal treating samples were compared and *** phase composition of as-reflowed interconnects was Cu/Cu6Sn5 and transformed to Cu/Cu3Sn/Cu6Sn5 after thermal *** failure modes of as-reflowed,aged and temperature cycling test were found in three-dimensional network structure *** average shear strength of the as-reflowed and the thermal treatment bonding interconnections are 49.5 Mpa and 24.9 Mpa,respectively,and crack initiated and propagated that perpendicular to substrate during the aging *** fracture surfaces of the temperature treatment bonding interconnections after shearing test were characterized in *** results show that the Cu3Sn phases in Cu@Cu3Sn@Cu6Sn5 three-dimensional network structure affected its strength and fracture *** Cu-rich substrate side at the fracture surfaces is always regular while the bulk phases are often accompanied by shear bands and dimples.

关键词： microstructure evolution as-reflowed aging test temperature cycling shearing strength

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