检索结果-南通市图书馆

A generative deep learning framework for airfoil flow field prediction with sparse data

Chinese Journal of Aeronautics 2022年第1期35卷 470-484页

作者： Haizhou WU Xuejun LIU Wei AN hongqiang lyu MIIT Key Laboratory of Pattern Analysis and Machine Intelligence College of Computer Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Aerodynamic Noise Control Mianyang 621000China State Key Laboratory of Aerodynamics Mianyang 621000China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing 210023China College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Deep learning has been probed for the airfoil performance prediction in recent *** with the expensive CFD simulations and wind tunnel experiments,deep learning models can be leveraged to somewhat mitigate such expenses with proper ***,effective training of the data-driven models in deep learning severely hinges on the data in diversity and *** this paper,we present a novel data augmented Generative Adversarial Network(GAN),daGAN,for rapid and accurate flow filed prediction,allowing the adaption to the task with sparse *** presented approach consists of two modules,pre-training module and fine-tuning *** pre-training module utilizes a conditional GAN(cGAN)to preliminarily estimate the distribution of the training *** the fine-tuning module,we propose a novel adversarial architecture with two generators one of which fulfils a promising data augmentation operation,so that the complement data is adequately incorporated to boost the generalization of the *** use numerical simulation data to verify the generalization of daGAN on airfoils and flow conditions with sparse training *** results show that daGAN is a promising tool for rapid and accurate evaluation of detailed flow field without the requirement for big training data.

关键词： CFD Flow field Generative adversarial networks(GANs) Sparse data Supercritical airfoil

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On developing data-driven turbulence model for DG solution of RANS

引用

Chinese Journal of Aeronautics 2019年第8期32卷 1869-1884页

作者： Liang SUN Wei AN Xuejun LIU hongqiang lyu College of Computer Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211106China College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing 210093China

High-order Discontinuous Galerkin(DG) methods have been receiving more and more attentions in the area of Computational Fluid Dynamics(CFD) because of their high-accuracy property. However, it is still a challenge to obtain converged solution rapidly when solving the Reynolds Averaged Navier–Stokes(RANS) equations since the turbulence models significantly increase the nonlinearity of discretization system. The overall goal of this research is to develop an Artificial Neural Networks(ANNs) model with low complexity acting as an algebraic turbulence model to estimate the turbulence eddy viscosity for RANS. The ANN turbulence model is off-line trained using the training data generated by the widely used Spalart–Allmaras(SA) turbulence model before the Optimal Brain Surgeon(OBS) is employed to determine the relevancy of input *** the selected relevant features, a fully connected ANN model is constructed. The performance of the developed ANN model is numerically tested in the framework of DG for RANS, where the‘‘DG+ANN' method provides robust and steady convergence compared to the ‘‘DG+SA' method. The results demonstrate the promising potential to develop a general turbulence model based on artificial intelligence in the future given the training data covering a large rang of flow conditions.

关键词： Artificial neural network Discontinuous Galerkin method Fluid Optimal brain surgeon Spalart–Allmaras turbulence model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A mesh optimization method using machine learning technique and variational mesh adaptation

引用

Chinese Journal of Aeronautics 2022年第3期35卷 27-41页

作者： Tingfan WU Xuejun LIU Wei AN Zenghui HUANG hongqiang lyu MIITKey Laboratory of Pattern Analysis and Machine Intelligence College of Computer Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 211106China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing 210023China College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Computational mesh is an important ingredient that affects the accuracy and efficiency of CFD numerical *** light of the introduced large amount of computational costs for many adaptive mesh methods,moving mesh methods keep the number of nodes and topology of a mesh unchanged and do not increase CFD computational *** the state-of-the-art moving mesh method,the variational mesh adaptation approach has been introduced to CFD ***,quickly estimating the flow field on the updated meshes during the iterative algorithm is challenging.A mesh optimization method,which embeds a machine learning regression model into the variational mesh adaptation,is *** regression model captures the mapping between the initial mesh nodes and the flow field,so that the variational method could move mesh nodes iteratively by solving the mesh functional which is built from the estimated flow field on the updated mesh via the regression *** the optimization,the density of the nodes in the high gradient area increases while the density in the low gradient area *** examples are first used to verify the feasibility and effectiveness of the proposed *** then we use the steady subsonic and transonic flows over cylinder and NACA0012 airfoil on unstructured triangular meshes to test our *** show that the proposed method significantly improves the accuracy of the local flow features on the adaptive *** work indicates that the proposed mesh optimization approach is promising for improving the accuracy and efficiency of CFD computation.

关键词： CFD Flow field Machine learning Moving mesh method Regression models Variational mesh adaptation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Implicit discontinuous Galerkin method on agglomerated high-order grids for 3D simulations

引用

Chinese Journal of Aeronautics 2016年第6期29卷 1496-1505页

作者： Qin Wanglong lyu hongqiang Wu Yizhao Zhou Shijie Chen Zhengwu Department of Aerodynamics Nanjing University of Aeronautics and AstronauticsNanjing 210016China China Aerodynamics Research and Development Center Mianyang 621000China

High quality of geometry representation is regarded essential for high-order methods to maintain their high-order accuracy. An agglomerated high-order mesh generating method is investigated in combination with discontinuous Galerkin(DG) method for solving the 3D compressible Euler and Navier-Stokes equations. In this method, a fine linear mesh is first generated by standard commercial mesh generation tools. By taking advantage of an agglomeration method, a quadratic high-order mesh is quickly obtained, which is coarse but provides a high-quality geometry representation, thus very suitable for high-order computations. High-order discretizations are performed on the obtained grids with DG method and the discretized system is treated fully implicitly to obtain steady state solutions. Numerical experiments on several flow problems indicate that the agglomerated high-order mesh works well with DG method in dealing with flow problems of curved geometries. It is also found that with a fully implicit discretized system and a p-sequencing method, the DG method can achieve convergence state within several time steps which shows significant efficiency improvements compared to its explicit counterparts.

关键词： Agglomeration Discontinuous Galerkin(DG) High-order Implicit scheme Navier-Stokes equations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An h-Adaptivity DG Method on Locally Curved Tetrahedral Mesh for Solving Compressible Flows

引用

Transactions of Nanjing University of Aeronautics and Astronautics 2020年第5期37卷 702-712页

作者： AN Wei HUANG Zenghui lyu hongqiang College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China Key Laboratory of Aerodynamic Noise Control China Aerodynamics Research and Development CenterMianyang 621000P.R.China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000P.R.China

For the numerical simulation of compressible flows,normally different mesh sizes are expected in different *** example,smaller mesh sizes are required to improve the local numerical resolution in the regions where the physical variables vary violently(for example,near the shock waves or in the boundary layers)and larger elements are expected for the regions where the solution is smooth.h-adaptive mesh has been widely used for complex ***,there are two difficulties when employing h-adaptivity for high-order discontinuous Galerkin(DG)***,locally curved elements are required to precisely match the solid boundary,which significantly increases the difficulty to conduct the"refining"and"coarsening"operations since the curved information has to be ***,h-adaptivity could break the partition balancing,which would significantly affect the efficiency of parallel *** this paper,a robust and automatic h-adaptive method is developed for high-order DG methods on locally curved tetrahedral mesh,for which the curved geometries are maintained during the ***,the reallocating and rebalancing of the computational loads on parallel clusters are conducted to maintain the parallel *** results indicate that the introduced h-adaptive method is able to generate more reasonable mesh according to the structure of flow-fields.

关键词： h-adaptivity discontinuous Galerkin(DG)method curved mesh tetrahedral mesh compressible flows

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于CFD高精度算法的雷电电磁场研究

引用

航空学报 2021年第S1期42卷 89-97页

作者：王子航吕宏强南京航空航天大学航空学院南京210016 气动噪声控制重点实验室绵阳621000 空气动力学国家重点实验室绵阳621000

雷电空间电磁场一直是电磁领域研究的热门,成熟的算法例如有限时域差分法(FDTD),传输线矩阵法(TLM)以及频域的矩量法(MoM)在计算雷电问题方面都有广泛的应用。由于计算流体力学(CFD)中的Euler方程与电磁学中的Maxwell方程有着相同的守... 详细信息

雷电空间电磁场一直是电磁领域研究的热门,成熟的算法例如有限时域差分法(FDTD),传输线矩阵法(TLM)以及频域的矩量法(MoM)在计算雷电问题方面都有广泛的应用。由于计算流体力学(CFD)中的Euler方程与电磁学中的Maxwell方程有着相同的守恒形式,而且采用间断伽辽金方法(DG)已经在流场问题上得到广泛的尝试,因此引入了基于计算流体力学的DG方法来离散时域Maxwell方程,并采用网格分区并行技术加速计算,使用基于DG的圆球雷达散射截面积(RCS)算例进行测试,数值结果一致表明DG算法在求解电磁场问题上的可行性,之后通过计算一段近场雷电通道的电场分布并与解析解、某算法仿真解对比,数据基本吻合,说明该方法适合于雷电电磁场的计算。

关键词：麦克斯韦方程雷电电磁场间断伽辽金计算流体力学时域电磁场仿真

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于高阶间断伽辽金数值方法的浸没边界法

引用

空气动力学学报 2023年第9期41卷 96-106页

作者：王婷婷吕宏强安慰南京航空航天大学航空学院南京210016

为了降低复杂边界条件下贴体网格生成难度,近年来基于笛卡尔网格的浸没边界法逐渐成为研究此类问题的主要数值方法之一,然而计算精度和计算效率仍然是此类方法目前面临的挑战。与传统的空间2阶精度的有限体积格式相比,空间精度为3阶或3... 详细信息

为了降低复杂边界条件下贴体网格生成难度,近年来基于笛卡尔网格的浸没边界法逐渐成为研究此类问题的主要数值方法之一,然而计算精度和计算效率仍然是此类方法目前面临的挑战。与传统的空间2阶精度的有限体积格式相比,空间精度为3阶或3阶以上的高精度方法具有空间精度高、数值分辨率高、数值耗散小的优点,而作为高精度数值方法之一的间断伽辽金方法在浸没边界方面的应用仍较少。本文将高阶间断伽辽金方法的高精度优势与浸没边界法无需贴体网格的优势结合起来,提出了适用于可压缩流动的高精度浸没边界法。其中边界条件采用体积惩罚方式实现,同时采用牛顿法迭代以及MPI并行提高计算效率,物面的数据重建采用插值点处的逆距离权重(IDW-IP)方法代替高阶格式下多项式插值方法。本文基于笛卡尔网格测试验证了二维定常和非定常情况下的数值模拟效果,并与传统贴体网格的计算结果进行了对比。

关键词：浸没边界法间断伽辽金体积惩罚界面函数数据重建

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental Research on a Feasible Building Insulation Material Based Reed in China

引用

Journal of Thermal Science 2025年第1期34卷 176-187页

作者： LIU Tiantian PENG Yizhe LIU Lifang CAI Chenghan WANG Shuang LI hongqiang College of Civil Engineering Hunan University College of Civil Engineering Hunan University of Science and Technology School of Energy and Power Jiangsu University of Science and Technology National Center for International Research Collaboration in Building Safety and Environment (NCIRCBSE) Hunan University Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education Hunan University

The seemingly useless reeds are prepared as thermal insulation materials,which not only meet the requirements of environmental sustainability but also enhance the added value of reeds,creating new economic *** hydrophobicity of raw biomass surfaces leads to problems such as weak bonding strength and non-dense structure in the formed materials,as well as issues related to the residual insect infestations on the *** this study,reed straw was used as the raw material,and foamed geopolymer was used as the binder to prepare building insulation materials based *** improve the interfacial adhesion performance between reed straw and foamed geopolymer,a thermochemical modification method-thermal carbonization,was *** this study,the mechanical properties and hydraulic properties of the studied materials with different degrees of surface thermal modification were tested,especially the fire resistance performance,and weathering resistance performance rarely found in published *** the surface thermal modification condition of reed straw was 250℃（30 min）,the comprehensive performance of reed-based building insulation materials was the best,when the studied material density was 321.3 kg/m3;the compressive strength was 0.59 MPa;the thermal conductivity was 0.101 W/（m·K）;the pH was 11.27;the moisture absorption rate was 25.1%,and the compressive strength loss rate in wet-dry cycles was 18.5%.In addition,it had excellent fire resistance performance and weathering resistance *** new material can be widely used to improve the thermal insulation of traditional buildings and as sandwich filler in prefabricated buildings,such as preparing insulating walls.

关键词： building insulation material based reed fire resistance performance interface adhesion properties pre-treatment of reeds weathering resistance performance

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Precise gradient separation of nanoparticles using reduced graphene oxide-polyoxomolybdate membranes

引用

Science China Chemistry 2025年第1期68卷 209-216页

作者： Yixin Yang Wanlei Zhao Ruoxuan Zheng hongqiang Li Wei Chen Yu-Fei Song State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Quzhou Institute for Innovation in Resource Chemical Engineering

The purification and size sieving of nanoparticles （NPs） represents a significant scientific ***,the r GO-polyoxometalates (POMs=PMo12,Mo132and Mo368) membranes were fabricated successfully via a simple and scalable POMsassisted in-situ photoreduction *** the mass ratio of r GO to PMo12was 1:30,the resultant r GO-PMo12membranes with highly ordered and uniform nanochannels of 1.0 nm can be obtained,which showed an accurate carbon quantum dots（CQDs） separation with a cut-off size approximately 1.0 *** increase of the size of the interlayered POMs from PMo12（1.0 nm）,{Mo132}（2.9 nm） to{Mo368}（3.8 nm）,the resultant r GO-PMo12,r GO-Mo132and r GO-Mo368exhibited precise gradient separation of CQDs and Au nanoparticles by size exclusion *** results pave a promising way to construct new twodimensional （2D） membranes for highly efficient size-selective separation.

关键词： reduced graphene oxide polyoxometalates membranes gradient separation nanoparticles

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于多输出高斯过程的超临界翼型优化

引用

空气动力学学报 2015年第6期33卷 728-732,746页

作者：吴宽展刘学军吕宏强南京航空航天大学计算机科学与技术学院江苏南京210016 南京航空航天大学航空宇航学院江苏南京210016

提出了一种基于多输出高斯过程(MOGP)回归模型和模拟退火算法相结合的翼型优化方法。采用拉丁超立方抽样方法在设计空间内构造一系列样本点,其中优化设计采用CST参数化方法对翼型的几何外形进行参数化表示。通过CFD流体计算得到其响应... 详细信息

提出了一种基于多输出高斯过程(MOGP)回归模型和模拟退火算法相结合的翼型优化方法。采用拉丁超立方抽样方法在设计空间内构造一系列样本点,其中优化设计采用CST参数化方法对翼型的几何外形进行参数化表示。通过CFD流体计算得到其响应值来建立初始的MOGP代理模型。以阻力最小化为设计目标,考虑面积、升力等约束条件。通过单点优化和多点优化试验表明,发展的翼型优化设计方法达到了优化设计的目的,同时也说明基于MOGP模型的优化设计方法在气动优化设计中的应用是可行的。

关键词：翼型优化设计输出高斯过程 CST参数化方法模拟退火算法超临界翼型

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：