检索结果-南通市图书馆

STUDIES ON THE NUMERICAl SIMULATION OF UNSTEADY FLOWS

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1995年第3期7卷 104-106页

作者： lu xi-yun(University of Science and Technology of China, Hefei 230026, P. R. China)Supervisor: Prof. Tong Bing-gang, Zhuang Li-xian, Yin xie-yuan(University of Science and Technology of China, Hefei 230026, P. R. China)

Some typical unsteady problems that are mainly dominated by shock waves,vortices, or both of them have been numerically simulated in the present study. The time history of unsteady flows is time-accurately computed and analyzed. The main factors influencing the unsteady flow features are disc-ussed. Furthermore, the key points for achieving time-accurate and cost-effective numerical simulations are systematically summarized. The whole dissertation is divided into three parts: the first, the numerical simulation of unsteady compressible inviscid flows; the second, the numerical simulation of unsteady incompressible viscous flows; and the last, studies on unsteady flow numerical simulation methods. The main contributions of this dissertation consist of : (1) The construction methods of total variation diminishing (TVD)schemes are analyzed in general, and a symmetric TVD scheme is developed in special: (2) The time-varying transonic flow fields and their influence on force features for a transonicperiodically pitching airfoil are successfully studied; (3) Using the same approach as before, theunsteady flow structures of a moving shock interacting with a vortex and with a vortex pair areinvestigated; (4) The numerical simulation of the near wake complex vortex formation for acircular cylinder oscillating in arbitrary directions in a free stream has ben conducted throughouta wide range of oscillation parameters. Many experimentally investigated phenomena areduplicated and even renewed numerically. A parameter map in the amplitude-frequency plane,showing restons of vortex shedding formation, is given. The influences of oscillation parametersand Reynolds numbers on the force characters and on the time-varying flow structures areexplained; (5) The force characters and vortex structures in the near wake of the pitching ortranslating air foils oscillating around a high incidence angle are successfully predicted bynumerically solving the Navier-Stokes equations; (6) Some key p

关键词： unsteady flow viscous flow numerical method

在线全文

学校读者我要写书评

暂无评论

可压缩双组分混合层的直接数值模拟研究

中国科学技术大学学报 2007年第10期37卷 1273-1279页

作者：孙小波范学军陆夕云中国科学技术大学近代力学系安徽合肥230027 中国科学院力学研究所北京100080

通过数值求解可压缩Navier-Stokes方程模拟了三维可压缩双组分混合层问题,着重研究了双组分密度比和可压缩效应对混合层发展演化的影响.研究表明,随着密度比的增大,混合层扰动增长率降低.在混合层发展初期,可压缩性作用尤其是斜压效应... 详细信息

通过数值求解可压缩Navier-Stokes方程模拟了三维可压缩双组分混合层问题,着重研究了双组分密度比和可压缩效应对混合层发展演化的影响.研究表明,随着密度比的增大,混合层扰动增长率降低.在混合层发展初期,可压缩性作用尤其是斜压效应对旋涡的发展起主导作用;在混合层发展后期,可压缩性影响减弱,旋涡的拉伸扭转效应占主导作用.同时,还分析讨论了可压缩混合层中湍流的转捩及拟序结构的演化过程.

关键词：双组分密度比可压缩混合层直接数值模拟

无限翼展后掠翼大迎角绕流和涡控制的数值模拟

在线全文

学校读者我要写书评

暂无评论

空气动力学学报 2000年第3期18卷 264-271页

作者：舒桃陆夕云杨国伟庄礼贤中国科学技术大学力学和机械工程系合肥230026

通过数值求解Navier Stokes方程 ,研究了无限翼展直后掠翼在不同后掠角下的大迎角粘性分离流 ,探讨了后掠角对流场结构和升阻力特性的影响。基于对流动特性的机理分析 ,文中进一步数值模拟了无限展长后掠翼带表面吹吸气的大迎角绕流 ,... 详细信息

通过数值求解Navier Stokes方程 ,研究了无限翼展直后掠翼在不同后掠角下的大迎角粘性分离流 ,探讨了后掠角对流场结构和升阻力特性的影响。基于对流动特性的机理分析 ,文中进一步数值模拟了无限展长后掠翼带表面吹吸气的大迎角绕流 ,研究了以非定常质量引射作为外激发手段对后掠翼前缘涡形成、发展和脱泻。

关键词：后掠翼涡控制大迎角绕流数值模拟

在线全文

学校读者我要写书评

暂无评论

飞行和游动的生物运动力学和仿生技术研究

中国科学技术大学学报 2007年第10期37卷 1159-1163页

作者：陆夕云杨基明尹协振童秉纲中国科学技术大学近代力学系中国科学技术大学近代力学系安徽合肥230027 中国科学院研究生院生物运动力学实验室北京100049

飞行与游动的生物运动力学是一门以流体力学为先导的交叉科学,我们采用活体观测、实验测量、数值模拟和理论分析多种手段,以及力学和生物学相结合的综合研究方法,系统地开展了关于飞行和游动的生物运动力学以及相关的仿生技术研究.论文... 详细信息

飞行与游动的生物运动力学是一门以流体力学为先导的交叉科学,我们采用活体观测、实验测量、数值模拟和理论分析多种手段,以及力学和生物学相结合的综合研究方法,系统地开展了关于飞行和游动的生物运动力学以及相关的仿生技术研究.论文从生物活体实验测试及其动力学特性、生物运动的拍动推进和波状摆动推进机理、理论分析和理论模化、水下仿生机器研制等几个方面分别简要介绍我们近期的主要研究进展.

关键词：飞行和游动生物力学生物外部流体力学拍动推进波状摆动推进仿生技术

二维翼大迎角绕流湍流模型及涡控制的数值研究 稹⑸缁岜U匣稹⒈O展镜取8没鹂梢怨⑿姓?,向公众、机构投资者、企业、证券基金、保险公司等进一步筹措资金 ,也可通过担保基金担保向银行贷款。总之

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

中国科学技术大学学报 2000年第4期30卷 414-421页

作者：舒桃余永亮陆夕云庄礼贤中国科学技术大学力学和机械工程系合肥230026

通过数值求解雷诺平均N S方程 ,研究了二维翼型的大迎角粘性绕流 ,并分析了翼型的近场旋涡分离流动特性 .基于流动机理分析 ,文中进一步开展了二维非定常“质量引射”的数值分析 ,旨在对流场进行控制 ,探讨提高翼型升力的有效途径 .同... 详细信息

通过数值求解雷诺平均N S方程 ,研究了二维翼型的大迎角粘性绕流 ,并分析了翼型的近场旋涡分离流动特性 .基于流动机理分析 ,文中进一步开展了二维非定常“质量引射”的数值分析 ,旨在对流场进行控制 ,探讨提高翼型升力的有效途径 .同时还比较了两种典型湍流模型 (BL模型和JK模型 )对这类复杂流动计算结果的影响 .

关键词：湍流模型涡控制数值模拟二维机翼大迎角绕流

LiDAR-Visual SLAM with Integrated Semantic and Texture Information for Enhanced Ecological Monitoring Vehicle Localization

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2025年第1期82卷 1401-1416页

作者： Yiqing lu Liutao Zhao Qiankun Zhao Foreign Environmental Cooperation Center Ministry of Ecology and Environment of PRCBeijing100035China Beijing Computing Center Co. Ltd.Beijing Academy of Science and TechnologyBeijing100083China Beijing Guyu Interactive Artificial Intelligence Application Co. Ltd.Beijing100024China

Ecological monitoring vehicles are equipped with a range of sensors and monitoring devices designed to gather data on ecological and environmental *** vehicles are crucial in various fields,including environmental science research,ecological and environmental monitoring projects,disaster response,and emergency management.A key method employed in these vehicles for achieving high-precision positioning is LiDAR(lightlaser detection and ranging)-Visual Simultaneous Localization and Mapping(SLAM).However,maintaining highprecision localization in complex scenarios,such as degraded environments or when dynamic objects are present,remains a significant *** address this issue,we integrate both semantic and texture information from LiDAR and cameras to enhance the robustness and efficiency of data ***,semantic information simplifies the modeling of scene elements,reducing the reliance on dense point clouds,which can be less ***,visual texture information complements LiDAR-Visual localization by providing additional contextual *** incorporating semantic and texture details frompaired images and point clouds,we significantly improve the quality of data association,thereby increasing the success rate of *** approach not only enhances the operational capabilities of ecological monitoring vehicles in complex environments but also contributes to improving the overall efficiency and effectiveness of ecological monitoring and environmental protection efforts.

关键词： LiDAR-Visual simultaneous localization and mapping integrated semantic texture information

A quantum-search-based multi-classifier for image recognition

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 21-31页

作者： lu Liu xingyu Wu lufan Zhang Chuan Wang School of Artificial Intelligence Beijing Normal University Applied Optics Beijing Area Major Laboratory Beijing Normal University

The multi-class classification of images is a pivotal challenge within the realm of image processing. As the volume of visual data continues to expand, there is a burgeoning interest in harnessing the unique capabilities of quantum computation to augment the efficiency of classification tasks. However, many existing methods for training quantum image multi-classifiers parallel classical machine learning techniques, where the requisite circuit measurements increase linearly with the volume of training data. This work introduces a novel approach for training a quantum image multi-classifier based on the quantum search algorithm. We have meticulously conducted rigorous experiments on a handwritten digit dataset, a classic benchmark in the field. The results have been meticulously compared with previous works, and the comparative analysis not only validates the efficiency of our proposed approach, requiring only O(N/b) measurements during training, but also highlights a significant quadratic speedup of the algorithm.

关键词： quantum computation image recognition quantum search algorithm

Unraveling the origins of PGY-sRNA-6,BZL-sRNA-20,and XKC-sRNA-h3

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Life Sciences 2025年

作者： Shanfa lu State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs Institute of Medicinal Plant DevelopmentChinese Academy of Medical Sciences&Peking Union Medical College Engineering Research Center of Chinese Medicine Resource Ministry of Education

Dear Editor,The regulatory role of herbal sRNAs in humans and animals is an interesting research ***,current evidence is insufficient to conclude that herbal sRNAs are novel precision medicines.I previously showed that HJT-sRNA-m1-HJT-sRNA-m8,identified as herbal sRNAs previously (Du et al.,2019),may be derived from humans and/or animals(lu,2023).To minimize errors during herbal sRNA analysis,I provided a list of matters needing special attention and proposed problem-solving solutions for researchers working on sRNA cross-kingdom regulation (lu,2023).

关键词：

A numerical study of fluid injection and mixing under near-critical conditions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第3期28卷 559-571页

作者： Hua-Guang Li xi-yun lu Vigor Yang Department of Modern Mechanics University of Science and Technology of China230026 HefeiChina School of Aerospace Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

Nitrogen injection under conditions close vicinity of the liquid-gas critical point is studied numerically. The fluid thermodynamic and transport properties vary drasti- cally and exhibit anomalies in the near-critical regime. These anomalies can cause distinctive effects on heat-transfer and fluid-flow characteristics. To focus on the influence of ther- modynamics on the flow field, a relatively low injection Reynolds number of 1 750 is adopted. For comparisons, a reference case with the same configuration and Reynolds number is simulated in the ideal gas regime. The model accommodates full conservation laws, real-fluid thermody- namic and transport phenomena. Results reveal that the flow features of the near-critical fluid jet are significantly differ- ent from their counterpart. The near-critical fluid jet spreads faster and mixes more efficiently with the ambient fluid along with a more rapidly development of the vortex pairing pro- cess. Detailed analysis at different streamwise locations in- cluding both the flat shear-layer region and fully developed vortex region reveals the important effect of volume dilata- tion and baroclinic torque in the near-critical fluid case. The former disturbs the shear layer and makes it more unstable. The volume dilatation and baroclinic effects strengthen the vorticity and stimulate the vortex rolling up and pairing pro- cess

关键词： Liquid-gas critical point Real-fluid Fluid in-jection Shear layer instability Vortical dynamics