数值研究激波与旋涡的相互作用

从非定常形式的Euler方程出发,数值模拟了运动激波与旋涡相互作用的非定常流动过程。为保证激波具有较高的分辨率,采用对称型TVD格式进行了数值计算。结果表明。这样可以有效地模拟流场中一些复杂的流动现象,如激波变形、激波分叉和三波点的形成,以及旋涡结构的变化过程等,并与已有的实验流动显示相符良好。同时,也是对TVD格式求解这类问题的一次初步尝试。     

一种改进的分层剪切湍流亚格子尺度模型及其应用

提出了一种新型的分层剪切湍流应力和湍流热通量的动力学亚格子尺度(SGS)模型,并就热分层槽道湍流问题,计算验证了该模型的正确性.采用大涡模拟方法和该动力学亚格子尺度模型,数值研究了在浮力和剪切双重作用下的稳定分层和不稳定分层槽道热剪切湍流,探讨了某些湍流特性随Richardson数的变化规律,并分析了相关的流动物理机制.     

Curvature Effect on Compressible Turbulent Flow over a Wavy Wall

A fully developed compressible turbulent flow in a channel with a lower wavy wall and a upper plane wall is studied using large eddy simulation. We mainly attempt to deal with the curvature effect on compressible turbulent flow over the wavy wall. Some typical quantities including the mean turbulence statistics, dilatation and baroclinic terms in the enstrophy equation, turbulent kinetic energy budgets and the near-wall turbulent structures are analysed. The results obtained in this study provide physical insight into the understanding of the effects of curvature and compressibility on wall-bounded compressible turbulent flow.     

An improved dynamic subgrid-scale model and its application to large eddy simulation of stratified channel flows

In the present paper, a new dynamic subgrid-scale (SGS) model of turbulent stress and heat flux for stratified shear flow is proposed. Based on our calculated results of stratified channel flow, the dynamic subgrid-scale model developed in this paper is shown to be effective for large eddy simulation (LES) of stratified turbulent shear flows. The new SGS model is then applied to the LES of the stratified turbulent channel flow to investigate the coupled shear and buoyancy effects on the behavior of turbulent statistics, turbulent heat transfer and flow structures at different Richardson numbers.     

工程科学的践行者——纪念童秉纲院士

中国科学院院士童秉纲教授(1927—2020)是流体力学家、教育家,工程科学的践行者.文中简要介绍了童秉纲先生的生平,着重回顾了童先生在非定常流与涡运动、生物运动力学、气动热力学等流体力学3个分支学科领域对工程科学思想的实践,最后介绍了童先生对我国力学教育的杰出贡献.     

超常环境力学领域研究新进展——《力学学报》极端力学专题研讨会综述报告

介绍了超常环境力学领域的相关研究背景,综述了《力学学报》极端力学专题研讨会的学术报告与前沿问题研讨.以极端力学关注的学科问题为视点,聚焦深海、深空、超高温、超高速等具有国家重大需求背景的研究方向,分别介绍了超常环境力学领域的重要成果与最新研究进展.通过这次会议,《力学学报》编辑部努力探索一种新的学术交流模式,能够及时将...     

郑哲敏先生逝世周年纪念专刊序

<正>2022年8月25日是我刊原主编郑哲敏先生逝世一周年.郑哲敏先生(图1)是我国著名力学家,中国科学院院士、中国工程院院士、美国国家工程院外籍院士, 2012年度国家最高科学技术奖获得者.他创立了爆炸力学学科及相关的研究领域;领导了材料力学、非线性力学、海洋工程力学等学科的建设和发展;倡导了计算力学、流固耦合、非常规能源、人工智能等领域的研究,为我国现代力学的发展做出了重大贡献.     

关于飞行和游动的生物力学研究

论述了飞行和游动生物力学的任务和意义,以及重大科学问题和与仿生技术相关的重大需求,并概要地介绍了与生物外部流体力学有关的科学问题、研究现状以及我国现有的研究基础和特色.文中针对如下若干重点科学问题进行了论述,具体包括Gray疑题及鱼类阻力的测定问题、鱼类机动运动的特征和机理、鱼类游动的流-固耦合及整体模化等交叉问题、昆虫运动的非定常流动控制机理和能耗、昆虫翼的柔性变形效应及抗风机制、昆虫和鱼的自由运动的运动学和动力学测量.图0参72      

Three-dimensional instability of an oscillating viscous flow past a circular cylinder

IntroductionTheunsteadyflowpastacircularcylinderhasreceivedagreatdealofattentionowingmainlytoitstheoreticalandpracticalsignificance .Theflowgeneratedbytheoscillationofthecylinder,oroscillatingflowsaroundthecylinder,canbecharacterizedbytwoparameters.OneistheKeulegan_Carpenternumber,definedasKC =UmT/D ,andtheotheristheReynoldsnumberRe=UmD/ν,orafrequencyparameter,definedasβ=D2 / (νT) =Re/KC) ,whichisoftenusedtoreplacetheReynoldsnumberasthesecondparameter.Here,Umisthemaximumvelocityofth…     

Turbulent Boundary Layer Control via a Streamwise Travelling Wave Induced by an External Force

Turbulent boundary layer control via a streamwise travelling wave is investigated based on direct numerical simulation of an incompressible turbulent channel flow. The streamwise travelling wave is induced on one side wall of the channel by a spanwise external force, e.g., Lorenz force, which is con~ned in the viscous sublayer. As the control strategy used in this study has never been examined, we pay our attention to its efficiency of drag control. It is revealed that the propagating direction of the travelling wave, i.e., the downstream or upstream propagating direction with respect to the streamwise flow, has an important role on the drag control, leading to a significant drag reduction or enhancement for the parameters considered. The coherent structures of turbulent boundary layer are altered and the underlying mechanisms are analysed. The results obtained provide physical insight into the understanding of turbulent boundary layer control.