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Theoretical & Applied Mechanics Letters 2024年第2期14卷 76-81页

作者： Jianlin Huang rundi qiu Jingzhu Wang Yiwei Wang Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Guangdong Aerospace Research Academy Guangzhou 511458China

Multi-scale system remains a classical scientific problem in fluid dynamics,biology,*** the present study,a scheme of multi-scale Physics-informed neural networks is proposed to solve the boundary layer flow at high Reynolds numbers without any *** flow is divided into several regions with different scales based on Prandtl's boundary *** regions are solved with governing equations in different *** method of matched asymptotic expansions is used to make the flow field continuously.A flow on a semi infinite flat plate at a high Reynolds number is considered a multi-scale problem because the boundary layer scale is much smaller than the outer flow *** results are compared with the reference numerical solutions,which show that the msPINNs can solve the multi-scale problem of the boundary layer in high Reynolds number *** scheme can be developed for more multi-scale problems in the future.

关键词： Physics-informed neural networks(PINNs) Multi-scale Fluid dynamics Boundary layer

Dynamic mode decomposition and reconstruction of transient cavitating flows around a Clark-Y hydrofoil

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Theoretical & Applied Mechanics Letters 2020年第5期10卷 327-332页

作者： rundi qiu Renfang Huang Yiwei Wang Chenguang Huang Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

The transient cavitating flow around the Clark-Y hydrofoil is numerically investigated by the dynamic mode decomposition with *** on the ranking dominant modes,frequencies of the first four modes are in good accordance with those obtained by fast Fourier ***,the cavitating flow field is reconstructed by the first four modes,and the dominant flow features are well captured with the reconstructed error below 12%when compared to the simulated flow *** paper offers a reference for observing and reconstructing the flow fields,and gives a novel insight into the transient cavitating flow features.

关键词： Transient cavitating flow Dynamic mode decomposition(DMD) Reconstructed flow field

Studies on two-bubble energy transfer model with radiant-receiver structure

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Acta Mechanica Sinica 2022年第11期38卷 26-35页

作者： Zhendong Bian Jingzhu Wang Bo Yin Yongjiu Wang rundi qiu Yiwei Wang Tezhuan Du Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Engineering Science University of Chinese Academy of SciencesBeijing100049China School of Future Technology University of Chinese Academy of SciencesBeijing100049China

A two-bubble model with radiate(αbubble)-receive(βbubble)structure is constructed to study the energy transfer from one bubble to *** influence of the non-dimensional distance d and the initial energy ratioψon the energy transfer rate is investigated via numerical *** relative received energyε,relative jet energy J,and energy transfer ratesηare defined to quantify energy *** show that the energy transfer rate decreases with the increase of d andψwhen the two bubbles’initial radius is *** the increase of d,the interactions between two bubbles are weakened,and the relative received energy satisfies the law ofε∝1/d^(2).With the increase ofψ,the maximum inner pressure of theβbubble increase first and then decreases,while the jet energy of bubbleβchanges with the law of J∝ψ.It is found that the energy storage capacity increases with the bubble radius by simulating different bubble radius ratios.

关键词： Bubble Energy transfer Radiant-receiver structure Volume of fluid method

改进的物理融合神经网络在瑞利-泰勒不稳定性问题中的应用

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力学学报 2022年第8期54卷 2224-2234页

作者：丘润荻王静竹黄仁芳杜特专王一伟黄晨光中国科学院力学研究所流固耦合系统力学重点实验室北京100190 中国科学院大学未来技术学院北京100049 中国科学院大学工程科学学院北京100049 中国科学院合肥物质科学研究院合肥230031

基于相场法的物理融合神经网络PF-PINNs被成功用于两相流动的建模,为两相流动的高精度直接数值模拟提供了全新的技术手段.相场法作为一种新兴的界面捕捉方法,其引入确保了界面的质量守恒,显著提高了相界面的捕捉精度;但是相场法中高阶... 详细信息

基于相场法的物理融合神经网络PF-PINNs被成功用于两相流动的建模,为两相流动的高精度直接数值模拟提供了全新的技术手段.相场法作为一种新兴的界面捕捉方法,其引入确保了界面的质量守恒,显著提高了相界面的捕捉精度;但是相场法中高阶导数的存在也降低了神经网络的训练速度.为了提升计算训练过程的效率,本文在PF-PINNS框架下,参考深度混合残差方法 MIM,将化学能作为辅助变量以及神经网络的输出之一,并修改了物理约束项的形式,使辅助变量与相分数的关系式由硬约束转为了软约束.上述两点改进显著降低了自动微分过程中计算图的规模,节约了求导过程中的计算开销.同时,为了评估建立的PF-PINNS在雷诺数较高、计算量较大的场景中的建模能力,本文将瑞利-泰勒RT不稳定性问题作为验证算例.与高精度谱元法的定性与定量对比结果表明,改进PF-PINNs有能力捕捉到两相界面的强非线性演化过程,且计算精度接近传统算法,计算结果符合物理规律.改进前后的对比结果表明,深度混合残差方法能够显著降低PF-PINNS的训练用时.本文所述方法是进一步提升神经网络训练速度的重要参考资料,并为探索高精度智能建模方法提供了全新的见解.

关键词：瑞利-泰勒不稳定性深度混合残差方法物理融合神经网络两相流

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随着邦德数减小球体入水空泡闭合类型的探究

Acta Mechanica Sinica 2023年第6期39卷 56-66页

作者：钟玉雪杜岩丘润荻肖志坚黄荐王志英王静竹王一伟 Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China

入水空泡的演化在自然界和工程领域中出现了有趣的动态现象.由于很难推动一个小球高速撞击水面,因此空泡的演化和闭合类型在Bo小于10−2时仍未得到解决.在本研究中,进行了一个基于激光驱动原理的实验,可将小球体加速到数百米每秒.在1~7.5... 详细信息

入水空泡的演化在自然界和工程领域中出现了有趣的动态现象.由于很难推动一个小球高速撞击水面,因此空泡的演化和闭合类型在Bo小于10−2时仍未得到解决.在本研究中,进行了一个基于激光驱动原理的实验,可将小球体加速到数百米每秒.在1~7.57×10^(-2)的Bo范围内,空泡闭合类型可分为准静态、浅闭合、深闭合和表面闭合.通过分析空泡颈部的横截面特征,研究了从浅闭合到深闭合的过渡机制.随着Bo值的进一步降低(5.69×10^(-2)~8.41×10^(-3)),浅闭合直接转变为表面闭合,因为颈部横截面的夹断时间随着Bo值的降低而降低,因此,深闭合消失了.最后,通过改变We和Bo进行参数研究,得到了两个边界.We≈64是准静态和浅闭合之间的过渡,We≈326是浅闭合和表面闭合之间的过渡.

关键词：空泡闭合过渡机制准静态高速撞击小球体激光驱动邦德数

针灸推拿联合功能锻炼在骨质疏松性腰椎退变合并糖尿病的效果分析

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智慧健康 2022年第35期8卷 91-95页

作者：陈龙安马春杰李秀兰毛润娣陈奕颍邱国庆东莞市中医院推拿科门诊广东东莞523000

目的分析针灸推拿联合功能锻炼在骨质疏松性腰椎退变合并糖尿病的效果。方法选择2020年1月-2021年3月在本院治疗的100例骨质疏松性腰椎退变合并糖尿病患者,根据研究对象实施治疗方式的不同分成参照组(针灸推拿治疗,50例)与实验组(针灸... 详细信息

目的分析针灸推拿联合功能锻炼在骨质疏松性腰椎退变合并糖尿病的效果。方法选择2020年1月-2021年3月在本院治疗的100例骨质疏松性腰椎退变合并糖尿病患者,根据研究对象实施治疗方式的不同分成参照组(针灸推拿治疗,50例)与实验组(针灸推拿联合功能锻炼治疗,50例),对比这两组入选者治疗疗效、症状疼痛改善程度、机体炎性因子改善情况与不良反应发生情况。结果实验组的治疗总疗效(98.00%)高于参照组(80.00%)(P0.05)。结论针灸推拿联合功能锻炼治疗骨质疏松性腰椎退变合并糖尿病,能尽快缓解患者躯体疼痛感受,改善患者机体活动功能,促使其机体炎性因子水平大幅度降低,且不会引起太多不良反应,安全性高,值得推荐。

关键词：针灸推拿功能锻炼骨质疏松性腰椎退变糖尿病炎性因子镇痛效果