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Prediction of Flow Field Over Airfoils Based on Transformer Neural Network 基于变压器神经网络的翼型流场预测
4区 工程技术 Q4 MECHANICS Pub Date : 2023-10-12 DOI: 10.1080/10618562.2023.2259806
Jianbo Zhou, Rui Zhang, Lyu Chen
AbstractAirfoil flow field data acquisition is pivotal to the study of aerodynamics, traditionally relying on time-consuming computational fluid dynamics simulations or expensive wind tunnel tests. Herein, we introduce a new methodology leveraging Transformer Neural Network (TNN), which differs from conventional methodologies by employing self-attention mechanisms, to effectively predict these critical flow field data using historical data. A comprehensive set of experiments demonstrates the TNN model’s exceptional predictive accuracy, achieving over 95% across various airfoils under various operating conditions. Beyond accuracy and efficiency, we introduce an attention principle in our TNN model enhancing its interpretability. By aligning the TNN model’s attention distribution with the aerodynamic principles of airfoils, we illustrate how it utilises these geometric attributes in its predictions, thereby offering theoretical backing to its predictive outcomes. Our TNN model’s commendable accuracy, efficiency and interpretability illuminate the pathway for continued exploration in the fusion of deep learning with computational fluid dynamics.KEYWORDS: Deep learningTransformer Neural Networkairfoilflow field Disclosure statementNo potential conflict of interest was reported by the author(s).Data Availability StatementThe data that support the findings of this study are available from the corresponding author upon reasonable request.Additional informationFundingThis work was supported by Scientific Research Project of Department of Education of Hunan Province [grant number 21C1577]; Natural Science Foundation of Hunan Province [grant number 2022JJ60090].
摘要翼型流场数据采集是空气动力学研究的关键,传统上依赖于耗时的计算流体动力学模拟或昂贵的风洞试验。在此,我们引入了一种利用变压器神经网络(TNN)的新方法,该方法与传统方法不同,它利用自关注机制,利用历史数据有效地预测这些关键流场数据。一组全面的实验证明了TNN模型的卓越预测精度,在各种操作条件下的各种翼型中达到95%以上。除了准确性和效率之外,我们在TNN模型中引入了注意原则,增强了其可解释性。通过将TNN模型的注意力分布与翼型的空气动力学原理对齐,我们说明了它如何在预测中利用这些几何属性,从而为其预测结果提供理论支持。我们的TNN模型值得称赞的准确性,效率和可解释性为深度学习与计算流体动力学融合的持续探索指明了道路。关键词:深度学习变形神经网络翼型流场披露声明作者未报告潜在利益冲突。数据可用性声明支持本研究结果的数据可根据通讯作者的合理要求提供。项目资助:湖南省教育厅科研项目[批准号:21C1577];湖南省自然科学基金[批准号2022JJ60090]。
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引用次数: 0
A Unified Grid Approach Using Hamiltonian Paths for Computing Aerodynamic Flows 基于哈密顿路径的统一网格法计算气动流动
4区 工程技术 Q4 MECHANICS Pub Date : 2023-10-04 DOI: 10.1080/10618562.2023.2264198
Yong Su Jung, Bharath Govindarajan, James Baeder
AbstractA solution algorithm using Hamiltonian paths is presented as a unified grid approach for rotorcraft applications. Hidden line structures are robustly identified on general two- and three-dimensional unstructured grids with mixed elements, providing a framework for line-based solvers. A pure quadrilateral/hexahedral mesh is a prerequisite for line identification and enables approximate factorisation along the lines. The numerical efficiency obtained using the line-implicit method on various unstructured grids is better than that of the point-implicit method. Both finite-difference and gradient reconstructions are possible regardless of grid type. A combined reconstruction method is applied, which uses different reconstructions simultaneously but for different grid directions. Finally, the solution convergence rate is further improved using a preconditioned generalized minimal residual method (GMRES), where the preconditioning step is performed using the efficient line-implicit method.Keywords: Rotorcraft aerodynamicsunstructured gridcomputational efficiencyline-implicit methodgeneralized minimal residual method AcknowledgementsThe authors would like to acknowledge Dr. Roger Strawn (Army AFDD) and Dr. Rajneesh Singh (ARL) for their continued support of HAMSTR development. This work was supported by the National Supercomputing Center with supercomputing resources including technical support (KSC-2022-CRE-0197).Disclosure statementNo potential conflict of interest was reported by the author(s).
摘要提出了一种基于哈密顿路径的旋翼机统一网格求解算法。在一般的二维和三维混合单元非结构化网格上实现了隐线结构的鲁棒识别,为基于线的求解提供了框架。纯四边形/六面体网格是线识别的先决条件,并且可以沿线进行近似分解。线隐法在各种非结构化网格上的数值计算效率优于点隐法。无论网格类型如何,有限差分重建和梯度重建都是可能的。采用不同网格方向同时进行不同重构的组合重构方法。最后,采用预条件广义最小残差法(GMRES)进一步提高了解的收敛速度,其中预处理步骤采用有效的线隐式方法进行。关键词:旋翼飞机空气动力学非结构网格计算效率隐式方法广义最小残差法致谢作者感谢Roger Strawn博士(陆军AFDD)和Rajneesh Singh博士(ARL)对HAMSTR发展的持续支持。本工作由国家超级计算中心提供超级计算资源,包括技术支持(KSC-2022-CRE-0197)。披露声明作者未报告潜在的利益冲突。
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引用次数: 0
Fluid Flow Modelling Using Physics-Informed Convolutional Neural Network in Parametrised Domains 在参数化域使用物理信息卷积神经网络的流体流动建模
4区 工程技术 Q4 MECHANICS Pub Date : 2023-01-02 DOI: 10.1080/10618562.2023.2260763
Ondřej Bublík, Václav Heidler, Aleš Pecka, Jan Vimmr
AbstractWe design and implement a physics-informed convolutional neural network (CNN) to solve fluid flow problems on a parametrised domain. The goal is to compare the effectiveness of training based solely on CFD-generated training data with purely physics-informed training and training based on a combination of both. We consider the problem of incompressible fluid flow in a convergent-divergent channel with variable wall shape. A speciality of the designed neural network is the incorporation of the boundary condition directly in the CNN. A physics-informed CNN that uses a non-Cartesian mesh poses a challenge when evaluating partial derivatives. We propose a gradient layer that approximates the first and second partial derivatives by finite differences using Lagrange interpolation. Our analysis shows that the convergence of purely physics-informed training is slow. However, using a small training dataset in combination with physics-informed training can achieve results comparable to physics-uninformed training with a considerably larger training dataset.Keywords: Physics-informed neural networkconvolutional neural networkU-Netincompressible fluid flowfluid dynamics Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis research is supported by project GA21-31457S ‘Fast flow-field prediction using deep neural networks for solving fluid-structure interaction problems’ of the Grant Agency of the Czech Republic.
摘要设计并实现了一种基于物理信息的卷积神经网络(CNN),用于求解参数化域上的流体流动问题。我们的目标是比较单纯基于cfd生成的训练数据与纯粹基于物理的训练以及基于两者结合的训练的有效性。考虑变壁形收敛发散通道中不可压缩流体的流动问题。所设计的神经网络的一个特点是将边界条件直接引入到CNN中。在计算偏导数时,使用非笛卡尔网格的物理学CNN提出了一个挑战。我们提出了一个梯度层,利用拉格朗日插值的有限差分近似一阶和二阶偏导数。我们的分析表明,纯物理知识训练的趋同是缓慢的。然而,将一个小的训练数据集与物理信息训练相结合,可以获得与使用一个相当大的训练数据集进行物理信息训练相当的结果。关键词:物理信息神经网络卷积神经网络不可压缩流体流动流体动力学披露声明作者未报告潜在利益冲突。本研究得到捷克共和国资助局GA21-31457S项目“利用深度神经网络快速预测流固耦合问题”的支持。
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引用次数: 0
Wall-Resolved Large-Eddy Simulation of Flow Over a Three-Dimensional Gaussian Bump 三维高斯凸起上流动的壁面分辨大涡模拟
4区 工程技术 Q4 MECHANICS Pub Date : 2023-01-02 DOI: 10.1080/10618562.2023.2246391
Donald P. Rizzetta, Daniel J. Garmann
AbstractWall-resolved large-eddy simulations were carried out for the flow over a Gaussian bump configuration. The geometry and flow conditions were motivated by an experimental investigation, which was conducted in order to provide data for validating numerical modelling. The present computations were initiated as benchmark results that are accessible via wall-resolved large-eddy simulation. It was found that by increasing the bump height, the Reynolds number could be reduced and flow separation would occur. The modified bump then serves as a surrogate for the original Gaussian bump producing a smooth separated flow. Solutions to the unsteady three-dimensional compressible Navier-Stokes equations were obtained utilising a high-fidelity computational scheme and an implicit time-marching approach. Large-eddy simulations were performed and grid resolution studies were carried to ensure quality of computed results. Features of the flowfields are elucidated, and it was found that the time-mean surface streamline pattern had similar features to that of the experiment.Keywords: Smooth-Body separationGaussian bumplarge-eddy simulationhigh-order numerical methodcompact-differencing scheme Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis material is based upon work supported by the Air Force Office of Scientific Research under an award monitored by G. Abate. Computational resources were supported in part by grants of supercomputer time from the U. S. Department of Defense Supercomputing Resource Centers at the Stennis Space Center, MS, Vicksburg, MS, and Wright-Patterson AFB, OH.
摘要采用全分辨大涡模拟方法,对高斯凸包结构的流动进行了数值模拟。几何和流动条件是由实验调查激发的,为了验证数值模拟而进行的数据。目前的计算是作为基准结果开始的,可以通过壁面分辨大涡模拟获得。研究发现,增加凸起高度可以降低雷诺数,产生流动分离。然后,修改后的凹凸作为原始高斯凹凸的替代品,产生平滑的分离流。采用高保真的计算格式和隐式时间推进方法,得到了三维非定常可压缩Navier-Stokes方程的解。为了保证计算结果的质量,进行了大涡模拟和网格分辨率研究。阐明了流场的特征,发现时间平均表面流线型与实验结果具有相似的特征。关键词:光滑体分离;高斯碰撞涡模拟;高阶数值方法;紧致差分格式;本材料基于空军科学研究办公室在G. Abate监督下的一项奖励所支持的工作。计算资源部分由美国国防部超级计算资源中心提供的超级计算机时间支持,这些超级计算机资源中心位于密歇根州维克斯堡的斯坦尼斯航天中心和俄亥俄州的赖特-帕特森空军基地。
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引用次数: 0
A Lattice Boltzmann Front-Tracking Interface Capturing Method based on Neural Network for Gas-Liquid Two-Phase Flow 基于神经网络的气液两相流晶格Boltzmann前跟踪界面捕获方法
IF 1.3 4区 工程技术 Q4 MECHANICS Pub Date : 2023-01-02 DOI: 10.1080/10618562.2023.2246398
Bozhen Lai, Zhaoqing Ke, Zhiqiang Wang, Ronghua Zhu, Ruifeng Gao, Yu Mao, Ying Zhang
This paper presents a new method that accurately captures the interface of gas–liquid two-phase flow using a neural network-based lattice Boltzmann front-tracking interface capturing method. The motion of a single free-falling droplet is simulated using the Front Tracking Method (FTM), enabling the acquisition of information regarding the velocity field and interface points. The velocity field and interface points from the simulations are then utilised to generate input and output datasets for training the neural network (NN) models. Subsequently, the trained Bayesian regularised Back Propagation Neural Network (BRBPNN) model is integrated into the Lattice Boltzmann method (LBM), utilising the velocity field obtained from LBM simulation as input. The predicted LBM interface exhibits remarkable agreement with the FTM interface, as evidenced by a high correlation coefficient of 0.99945 for the ordinate value of the interface point in both methods. Therefore, the proposed method achieves precise positioning of the phase interface of LBM.
本文提出了一种基于神经网络的晶格玻尔兹曼前沿跟踪界面捕获方法,可以准确地捕获气液两相流的界面。利用前沿跟踪方法(FTM)模拟单个自由落体液滴的运动,从而获得有关速度场和界面点的信息。然后利用仿真得到的速度场和界面点来生成用于训练神经网络(NN)模型的输入和输出数据集。随后,将训练好的贝叶斯正则化反向传播神经网络(BRBPNN)模型集成到晶格玻尔兹曼方法(LBM)中,利用LBM仿真得到的速度场作为输入。预测的LBM界面与FTM界面具有显著的一致性,两种方法中界面点纵坐标值的相关系数均为0.99945。因此,该方法实现了LBM相界面的精确定位。
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引用次数: 0
Verification of a Pressure-Based Compressible Flow Solver 基于压力的可压缩流动求解器的验证
IF 1.3 4区 工程技术 Q4 MECHANICS Pub Date : 2023-01-02 DOI: 10.1080/10618562.2023.2242271
J. Muralha, L. Eça, C. Klaij
This paper presents Solution Verification exercises with the pressure-based compressible flow solver ReFRESCO for five test cases available in the NASA Turbulence Modeling Resource: the two-dimensional flows over a flat plate, a bump-in-channel, a DSMA661 airfoil and a multi-element airfoil and the three-dimensional flow of a bump-in-channel. Simulations are performed with the Favre-averaged continuity and Navier-Stokes equations using the Spalart & Allmaras turbulence model. ReFRESCO results are compared with reference data from density-based compressible flow solvers (CFL3D and FUN3D). two aspects of the implementation of the turbulence model are addressed: the calculation of the distance to the wall and the discretization scheme used in the convective terms of the turbulence model transport equation. Results of this study show perfect consistency with the reference data for the test cases that are not affected by the determination of the distance to the wall.
本文介绍了基于压力的可压缩流动求解器ReFRESCO的解决方案验证练习,用于NASA湍流建模资源中提供的五个测试用例:平面板,通道内碰撞,DSMA661翼型和多单元翼型的二维流动以及通道内碰撞的三维流动。利用Spalart & Allmaras湍流模型,采用favre平均连续性和Navier-Stokes方程进行了模拟。ReFRESCO的结果与基于密度的可压缩流动求解器(CFL3D和FUN3D)的参考数据进行了比较。讨论了紊流模型实现的两个方面:到壁面距离的计算和紊流模型输运方程对流项中使用的离散化方案。研究结果与参考数据完全一致,测试用例不受离墙距离确定的影响。
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引用次数: 0
Influence of the Downstream Vehicle Length on Train Aerodynamics Subjected to Crosswind 侧风作用下下游车辆长度对列车空气动力学的影响
IF 1.3 4区 工程技术 Q4 MECHANICS Pub Date : 2022-12-31 DOI: 10.36959/717/661
Zhuang Tianci, Li Wenhui, Liu Tanghong
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引用次数: 0
Thermal Radiation, Chemical Reaction and Viscous Dissipation Effects on MHD Mixed Convection Flow of Micro Polar Fluid with Stretching Surface in the Presence of Heat Generation/Absorption 热辐射、化学反应和粘滞耗散对生热/吸热条件下具有拉伸表面的微极流体MHD混合对流的影响
IF 1.3 4区 工程技术 Q4 MECHANICS Pub Date : 2022-12-31 DOI: 10.36959/717/662
Zigta Binyam
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引用次数: 0
Shape Optimization and Flow Analysis of Supersonic Nozzles Using Deep Learning 基于深度学习的超声速喷管形状优化与流动分析
IF 1.3 4区 工程技术 Q4 MECHANICS Pub Date : 2022-11-26 DOI: 10.1080/10618562.2023.2225416
Aref Zanjani, A. Tahsini, Kimia Sadafi, Fatemeh Ghavidel Mangodeh
Shape optimisation of supersonic nozzles is of crucial importance in designing propulsion systems and space thrusters. In order to optimise the profile of a supersonic nozzle, the properties of the flow inside the nozzle should be obtained. This paper proposes and verifies a new methodology for analysing flows and designing supersonic nozzles. Flow analysis has been conducted using the method of characteristics, Ansys Fluent and convolutional neural networks. It is shown that deep convolutional neural networks can reach high levels of accuracy in predicting supersonic flow behaviour inside the nozzle. Also, shape optimisation of the supersonic nozzle has been conducted using the genetic algorithm in Ansys Fluent and artificial neural networks. The proposed ANN can optimise the shape of a supersonic nozzle for the given throat diameter, outlet diameter and nozzle length with high accuracy.
超音速喷管的形状优化在推进系统和空间推力器设计中具有重要意义。为了优化超声速喷管的型面,必须了解喷管内部的流动特性。本文提出并验证了一种超声速喷管流动分析和设计的新方法。采用特征分析方法、Ansys Fluent和卷积神经网络进行了流动分析。研究表明,深度卷积神经网络在预测喷管内部超声速流动行为方面具有较高的精度。利用Ansys Fluent中的遗传算法和人工神经网络对超声速喷管进行了形状优化。所提出的人工神经网络可以在给定喉道直径、出口直径和喷嘴长度的情况下对超音速喷嘴形状进行高精度优化。
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引用次数: 1
Finite Element Numerical Simulation of Local Scour of a Three-Dimensional Cylinder under Steady Flow 定常流动条件下三维圆柱局部冲刷的有限元数值模拟
IF 1.3 4区 工程技术 Q4 MECHANICS Pub Date : 2022-11-26 DOI: 10.1080/10618562.2023.2221645
Dawei Peng, Lanhao Zhao, Chuanyuan Zhou, Jia Mao
Pile safety has received increasing attention in marine engineering, especially in the field of local scour. In this paper, a finite element numerical model is established for local scour around a cylinder in steady currents. The flow is described by unsteady Reynolds–averaged Navier–Stokes equations with a traditional turbulent closure model. The proposed scour model takes bed load into account. The Exner equation is solved to determine the bed variation and the moving mesh approach is used to capture the evolution of the bed. When the resulting slope exceeds the angle of repose, a novel sand-slide model based on Rodrigues' rotation formula is used to prevent simulation distortion. All the equations are discretized by the two-step Taylor–Galerkin algorithm, and the resulting approach is fast to implement with second-order accuracy in space. The numerical results are found to be in good agreement with the experimental data.
桩的安全问题在海洋工程领域,尤其是局部冲刷领域受到越来越多的关注。本文建立了稳定流条件下圆柱局部冲刷的有限元数值模型。用非定常reynolds - average Navier-Stokes方程和传统的湍流闭包模型来描述流动。提出的冲刷模型考虑了河床荷载。通过求解Exner方程确定床层的变化,采用移动网格法捕捉床层的演变。当产生的坡度超过休止角时,采用基于Rodrigues旋转公式的新型滑坡模型来防止模拟失真。采用两步Taylor-Galerkin算法对所有方程进行离散化,得到的方法在空间上具有二阶精度,实现速度快。数值计算结果与实验数据吻合较好。
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引用次数: 0
期刊
International Journal of Computational Fluid Dynamics
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