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Numerical simulations of FPSO with sloshing tanks in a random freak waves

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Journal of Hydrodynamics 2022年第3期34卷 491-498页

作者： Yuan Zhuang Guo Wang De-cheng Wan Jian-wei Wu Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Marine Design and Research Institute of China Shanghai200011China wuhan Second Ship Design and Research Institute Wuhan430205China

This paper presents a potential-viscous coupled method to simulate a floating production storage and offloading(FPSO)with two liquefied natural gas(LNG)sloshing tanks in a random freak wave.The potential theory uses high-order-spectral(HOS)method.The random wave is generated by HOS for 2000 s,and a freak wave is observed around 1830 s.The FPSO LNG model was firstly verified in regular waves using HOS-computational fluid dynamics(CFD)coupled method and validated the HOS-CFD coupled method can solve the ship motion coupled with sloshing tanks accurately.The FPSO with LNG tanks are then simulated in the freak wave,showed the coupling effects when the freak wave passes.With the existence of the sloshing tanks,the amplitude of the roll motion decreases and the period of roll motion changed.Wave breaking phenomenon can be observed when the wave crest of the freak wave encounters with the ship.

关键词： Ship motion with sloshing tank high-order-spectral-computational fluid dynamics(HOS-CFD)method naoe-FOAM-SJTU solver freak waves

Preliminary control of the air entrainment in bow wave based on the Liutex force method

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Journal of Hydrodynamics 2022年第3期34卷 483-490页

作者： Yi-ding Hu Jian-wei Wu De-cheng Wan Guo Wang Yi-qian Wang Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China wuhan Second Ship Design and Research Institute Wuhan430205China Marine Design and Research Institute of China Shanghai200011China School of Mathematical Science Soochow UniversitySuzhou215006China

Trails induced by air entrainment of bow wave breaking can be observed clearly around an advancing ship,making it prong to be detected and causing reduction in hydrodynamic performance.In breaking bow wave region,different scale of coherent vortex structures related closely to the air entrainment are generated.The formation and evolution of bubble clouds can be accounted partly by the swirling vortex flow of the jet plunging.In this work,high-fidelity simulation of the bow wave breaking around a rectangular thin plate is performed with the in-house code BAMR-SJTU.A Liutex force model is constructed to investigate the interaction between the free surface and vortices,and to explore the possibility of alleviating or controlling the air entrainment.This study is the first attempt to manipulate vortices corresponding to the air entrainment of the bow wave breaking.Some typical vortex structures based on the Liutex vortex identification method and the distribution of the vortex force are presented.Comparison of the vortex structures and the entrapped bubbles is conducted to illustrate the efficiency of Liutex force model in air entrainment control.

关键词： Bow wave breaking air entrainment coherent vortex structures Liutex force field model

Voice from China:nomenclature of the novel coronavirus and related diseases

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Chinese Medical Journal 2020年第9期133卷 1012-1014页

作者： Gui-Zhen wu jian-wei Wang Xu jian-Qing Asian-Pacific Biosafety Association Chinese Center for Disease Control and Prevention Research Center in National Institute for Viral Disease Control and Prevention Chinese Academy of Mediw cal Sciences and Peking Union Medical College Christophe Merieux Laboratory Institutes of Biomedical Sciences and Shanghai Public Health Clinical Center Fudan University Shanghai Institute of Emerging and Reemerging Infectious School of Translational Medicines at Shanghai Public Health Clinical Center Fudan University

Since early December 2019,the novel coronavirus has caused an outbreak of pneumonia that has claimed over 2000 lives,with more than 77,000 confirmed cases of infection by February 23,2020 in China.[1]The World Health Organization(WHO)recently named the disease caused by this new coronavirus as"coronavirus disease 2019(COVID-19)".The International Committee on Taxonomy of Viruses(ICTV)has named the new virus"severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)".[2]However,questions have been raised by different academic and professional bodies regarding whether the nomenclature is appropriate.

关键词： acute diseases respiratory

Biomolecular Topology:Modelling and Analysis

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Acta Mathematica Sinica,English Series 2022年第10期38卷 1901-1938页

作者： jian LIU Ke-Lin XIA Jie wu Stephen Shing-Toung YAU Guo-wei wei School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050024P.R.China Yanqi Lake Beijing Institute of Mathematical Sciences and Applications Beijing 101408P.R.China School of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 639798 Department of Mathematical Sciences Tsinghua UniversityBeijing 100084P.R.China Department of Mathematics&Department of Biochemistry and Molecular Biology&Department of Electrical and Computer Engineering Michigan State UniversityWells Hall 619 Red Cedar Road East LansingMI 48824-1027US

With the great advancement of experimental tools,a tremendous amount of biomolecular data has been generated and accumulated in various databases.The high dimensionality,structural complexity,the nonlinearity,and entanglements of biomolecular data,ranging from DNA knots,RNA secondary structures,protein folding configurations,chromosomes,DNA origami,molecular assembly,to others at the macromolecular level,pose a severe challenge in their analysis and characterization.In the past few decades,mathematical concepts,models,algorithms,and tools from algebraic topology,combinatorial topology,computational topology,and topological data analysis,have demonstrated great power and begun to play an essential role in tackling the biomolecular data challenge.In this work,we introduce biomolecular topology,which concerns the topological problems and models originated from the biomolecular systems.More specifically,the biomolecular topology encompasses topological structures,properties and relations that are emerged from biomolecular structures,dynamics,interactions,and functions.We discuss the various types of biomolecular topology from structures(of proteins,DNAs,and RNAs),protein folding,and protein assembly.A brief discussion of databanks(and databases),theoretical models,and computational algorithms,is presented.Further,we systematically review related topological models,including graphs,simplicial complexes,persistent homology,persistent Laplacians,de Rham-Hodge theory,Yau-Hausdorff distance,and the topology-based machine learning models.

关键词： Persistent homology topological data analysis biomolecular topology protein structure machine learning

Air bubble breakup in shear water flows generated by a plug conduit:An experimental investigation

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Journal of Hydrodynamics 2023年第6期35卷 1077-1088页

作者： Han wu Mao-lin Zhou wei-lin Xu Wang-ru wei jian-bo Li State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China PowerChina Chengdu Engineering Corporation Limited Chengdu610072China

In the context of a sudden contraction plug conduit,the near-wall area experiences a significant shearing effect of water flow,however,the extent to which this shearing effect occurs in bubble-water flow and the related variation mechanisms of air bubble size and number remain unclear.This study employs a model test method to investigate the diffusion process of bubble-water flow in a sudden contraction plug conduit.The size and number of bubbles,as well as their distribution along the shearing section under varying initial air volume conditions,are studied in detail using a high-speed image acquisition system.The experimental findings reveal a self-similar relationship between the number and size of bubbles and their cross-sectional distribution over time.The bubble number and size vary in three stages,i.e.,quasi-suspension,shearing,and shearing completion stages.The direction perpendicular to the conduit exhibits peak values in bubble number distribution over the three stages,with peak value location varying with the near-wall area.As time progresses,the peak value increases,and a larger initial air volume corresponds to a smaller distance of the peak value location from the wall.The size of air bubbles near the wall is consistent with the minimum diameter of air bubbles in shear flow and is hardly affected by the initial air volume.These results aid in comprehending the change law of two-phase water and air flow under a strong shearing effect in the plug conduit,and provide useful insights for hydraulic design in fluid engineering.

关键词： Air-water flows bubble properties air diffusion process plug conduits experimental study

The release and catabolism of ferulic acid in plant cell wall by rumen microbes:A review

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Animal Nutrition 2022年第2期9卷 335-344页

作者： Yan-Lu Wang wei-Kang Wang Qi-Chao wu Hong-jian Yang State Key Laboratory of Animal Nutrition College of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China

Ferulic acid(FA)is one of the most abundant hydroxycinnamic acids in the plant world,especially in the cell wall of grain bran,in comparison with forage and crop residues.Previous studies noted that FA was mainly linked with arabinoxylans and lignin in plant cell walls in ester and ether covalent forms.After forages were ingested by ruminant animals or encountered rumen microbial fermentation in vitro,these cross-linkages form physical and chemical barriers to protect cell-wall carbohydrates from microbial attack and enzymatic hydrolysis.Additionally,increasing studies noted that FA presented some toxic effect on microbial growth in the rumen.In recent decades,many studies have addressed the relationships of ester and/or ether-linked FA with rumen nutrient digestibility,and there is still some controversy whether these linkages could be used as a predicator of forage digestibility in ruminants.The authors in this review summarized the possible relationships between ester and/or ether-linked FA and fiber digestion in ruminants.Rumen microbes,especially bacteria and fungi,were found capable of breaking down the ester linkages within plant cell walls by secreting feruloyl and p-coumaroyl esterase,resulting in the release of free FA and improvement of cell wall digestibility.The increasing evidence noted that these esterases secreted by rumen microbes presented synergistic effects with xylanase and cellulase to effectively hydrolyze forage cell walls.Some released FA were absorbed through the rumen wall directly and entered into blood circulation and presented antioxidant effects on host animals.The others were partially catabolized into volatile fatty acids by rumen microbes,and the possible catabolic pathways discussed.To better understand plant cell wall degradation in the rumen,the metabolic fate of FA along with lignin decomposition mechanisms are needed to be explored via future microbial isolation and incubation studies with aims to maximize dietary fiber intake and enhance fiber digestion in ruminant animals.

关键词： Rumen microbes Ferulic acid Fiber digestion

Elaborate Scene Reconstruction with a Consumer Depth Camera

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International Journal of Automation and computing 2018年第4期15卷 443-453页

作者： jian-wei Li wei Gao Yi-Hong wu National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of SciencesBeijing 100080China University of Chinese Academy of Sciences Beijing 100049China

A robust approach to elaborately reconstruct the indoor scene with a consumer depth camera is proposed in this paper. In order to ensure the accuracy and completeness of 3D scene model reconstructed from a freely moving camera, this paper proposes new 3D reconstruction methods, as follows： 1） Depth images are processed with a depth adaptive bilateral filter to effectively improve the image quality; 2） A local-to-global registration with the content-based segmentation is performed, which is more reliable and robust to reduce the visual odometry drifts and registration errors; 3） An adaptive weighted volumetric method is used to fuse the registered data into a global model with sufficient geometrical details. Experimental results demonstrate that our approach increases the robustness and accuracy of the geometric models which were reconstructed from a consumer-grade depth camera.

关键词： 3D reconstruction image processing geometry registration simultaneous localization and mapping（SLAM） volumetricintegration.

Experimental investigation on cenosphere-aluminum syntactic foam-filled tubes under axial impact loading

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第11期24卷 978-990页

作者： Li WANG Boyi ZHANG jian ZHANG Yuexin jianG wei WANG Gaohui wu School of Civil Engineering Harbin Institute of TechnologyHarbin 150090China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of TechnologyHarbin 150090China Center for Metal Matrix Composites Engineering Technology Harbin Institute of TechnologyHarbin 150006China

A new syntactic foam material was prepared by screening three different average particle sizes of cenospheres(150,200,and 300μm)from industrial waste fly ash.Axial impact testing on syntactic foam filler and foam-filled tubes was conducted using a drop hammer test machine.The effects of parameters,such as the size of cenospheres and the impact velocity,on the mechanism of deformation,mechanical characteristics,and capacity for energy absorption of the specimen were investigated.On this basis,the differences in compressive properties exhibited by the syntactic foam-filled tubes under the two loading conditions were investigated.The results indicate that with the decrease in the average diameter of cenospheres,the initial peak crushing load and mean crushing load of foam-filled tubes increase,while the compression efficiency decreases.The specific energy absorption(SEA)of the syntactic foam-filled tube can reach 25 J/g.With the increase of impact velocity,the SEA of the specimen increases slightly.It was demonstrated that the syntactic foam-filled tube exhibits a higher effective energy absorption ratio under impact loading compared to quasi-static loading.

关键词： Cenosphere-aluminum syntactic foam Crashworthiness Mechanical properties Absorption of energy

New advances in fiber-reinforced composite honeycomb materials

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Science China(Technological Sciences) 2020年第8期63卷 1348-1370页

作者： wei XingYu XIONG jian WANG Jie XU wu Center for Composite Materials and Structures Harbin Institute of TechnologyHarbin 150001China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China Shanghai Aircraft Design and Research Institute Shanghai 201210China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China

In sandwich structures,lightweight cellular materials as the core hold the face sheets far away from the neutral axis to maximize the bending performance of the structure.Honeycomb materials as a major type of lightweight cellular materials have been widely applied in various fields,including aerospace,vehicle,marine,architecture and mechanical engineering,due to reliable mechanical properties and excellent designability.Using fiber-reinforced composites is an efficient method to develop ultralight honeycomb materials with superior mechanical behaviors.In recent years,fiber-reinforced composite honeycomb materials possessing lightweight and excellent mechanical performances have attracted noticeable attention to replacing traditional aluminum honeycombs and Nomex honeycombs.Compared to metal,polymer and Nomex paper,fiber-reinforced composites possess various merits,such as high specific stiffness and specific strength,excellent fatigue property,corrosion resistance and high-temperature resistance.Thus,the applications of fiber-reinforced honeycomb material for sandwich core have unlimited potential in hypersonic vehicles,long-range rockets,cargo vessels and protective systems.Although the fact that attention has been rapidly increasing,there is a lack of comprehensive reviews of new advances in the field of fiber-reinforced composite honeycomb materials.In this review,new advances reported by different scientists in the field of fiber-reinforced honeycomb materials have been reviewed and analyzed to provide an in-depth overview and knowledge for beginners in the field of ultralightweight and high-performance composite sandwich architectures.The challenges and prospects for the development of fiberreinforced honeycomb materials have also been presented.

关键词： composite honeycomb materials sandwich structures failure mechanism mechanical property