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A review of the study on the boundary slip problems of

Guojun Ma, Ping Zhou

2008, 38(3): 265-282. doi: 10.6052/1000-0992-2008-3-J2007-120

Abstract(3744)

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Abstract:
During recent years,great progress has been made in the study of boundary slip problemof fluid flow with the development of micro/nano test technologiesand molecular-dynamic simulation (MDS) technology. In general,boundary slip problem is studied through experimental observation,MDS, and numerical analysis. Experiments and MDS are usually usedfor discovering the boundary slip phenomena, revealing thephysical mechanism that triggers boundary slip, and investigatingthe effects of various factors. Numerical analysis is used tostudy the appropriate constitute model of boundary slip,computational algorithm, and the impact of boundary slip on thehydrodynamics of the flow. In this paper, we briefly review someearly research on the boundary slip problem, then review recentwork, and end with a discussion of future work and prospects ofthe boundary slip application.

Research advances of the microstructure and mechanical behavior of nacre

SONG Fan

2008, 38(3): 283-302. doi: 10.6052/1000-0992-2008-3-J2007-126

Abstract(2510)

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Nacre, ormother-of-pearl, a main structural material forming the innerlayer of mollusc shells, displays excellent mechanical properties.It became a hot research topic recently in biomimetic design andsynthesis for advanced engineering materials. The hierarchicalmicrostructure of this biological material is so well organizedthat its strength and toughness are far superior to the pureceramic that the material is made of. In this paper, we summarizerelevant studies on the microstructures, mechanical properties,and mechanical modeling of nacre. Problems in the study of nacreare pointed out and discussed briefly.

Developments in research on mechanical behavior of ferromagnetic shape memory alloys

2008, 38(3): 303-313. doi: 10.6052/1000-0992-2008-3-J2007-110

Abstract(2575)

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Ferromagnetic shapememory alloy (FSMA) is a new class of functional material. Inaddition to the general behaviors of traditionaltemperature-controlled and stress-controlled shape memory, FSMAcan produce large strains under an external application inmoderate magnetic fields. This ability makes FSMA suitable for awide range of applications. This paper reviews the research onmechanical behaviors of FSMA. It focuses on the study of themechanical behavior, and also includes the topic of theapplication of the materials. It summarizes the effects of thecrystal component, the magnetic field, the stress, and thetemperature on the mechanical behavior of the material. It alsosummarizes the developments of a constitutive model forferromagnetic shape memory alloy.

Advances in the study of methods and mechanism\\ of

2008, 38(3): 314-328. doi: 10.6052/1000-0992-2008-3-J2007-078

Abstract(2771)

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In the first section,we classify the control methods of vortex shedding in bluff bodywakes according to the control ideas that originate from thetheoretical models of vortex generation, and then brieflyintroduce the recent works of the control in china. In the secondsection, we present our work on a modified Strykowski \&Sreenivasan's method, in which the circular control element isreplaced by an element of strip or square cross-section. Theresult shows an improvement on suppression of vortex shedding froma circular cylinder and from a square cylinder at high Reynoldsnumber flow. The influence of the degree of control element'sbluffness on the suppression is investigated. In the thirdsection, the theoretical models of vortex generation are analyzedand examined by using experimental data. We conclude that themechanism of the element control is not related to the change ofseparation position or to the reduction of base suction, or to thechange of span-wise correlation of the flow, or to the preventionof interactions between the separated shear layers, but is relatedto the local modifications of the velocity profiles downstream thebluff body and the change in their instability nature. In thefinal section, we discuss the future study of the control elementmethod and the prospects for engineering applications.

The progresses of drop thermocapillary migration research

2008, 38(3): 329-338. doi: 10.6052/1000-0992-2008-3-J2007-052

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The migration of bubbles ordroplets in liquids is a very important topic in materials science,chemical engineering and fundamental researches. Under themicro-gravity condition, if the temperature gradient of thebackground flow field is non-zero, bubbles or droplets will movebecause of differences in interfacial tension on the drop surface. Suchmotion is termed Marangoni migration or thermocapillary migration.In this paper, the progresses of researches on the drop/bubblethermocapillary migration, including theoretical analysis, numericalsimulation and experimental studies, are reviewed. At present, thetheoretical analyses mainly focus on linear or weaknon-linear steady problems. Some numerical simulations were carried outon unsteady migration processes of drops with the Marangoninumber less than 100. When the heat convection effect isstrong(over 100), no numerical results were reported that are consistent with those from experiments. In this paper, we summarizeprevious research results, give our new numerical resultsof unsteady drop migration problems with large Marangoni numbers anddiscuss new phenomena under this condition. Finally, some problems in current studies are pointed out and the developmentof drop thermocapillary migration problems in future is discussed.

Review of turbulent drag-reducing flow and heat transferwith additives

2008, 38(3): 339-357. doi: 10.6052/1000-0992-2008-3-J2007-094

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Turbulent dragreduction by additives refers to the phenomenon that the turbulentfriction of a liquid flow in a pipe decreases significantly when high molecular polymer or some kinds of surfactant additives are added to the flow. Studies (experimental study,theoretical analysis, numerical simulation and application testsin real systems) over around a half century since its discoveryhave provided much understanding on the turbulent drag reductionphenomenon and its value in applications. Nevertheless, there arestill some aspects which need to be investigated further, forexample, the turbulent drag reduction mechanism. The currentresearch status in the field of turbulent drag-reducing flow andheat transfer with polymer or surfactant additives is reviewed inthis paper. The characteristics of turbulent drag-reducing flowand heat transfer are summarized in the following aspects:properties of turbulent drag reducers, mechanisms of turbulentdrag reduction with additives, mechanisms of convective heattransfer with turbulent drag reduction, and distribution of thevelocity and the heat transfer control in drag-reducing flow.Furthermore, the applications of turbulent drag reducers in theindustrial systems are discussed. Some new insights on themechanism of turbulent drag reduction by additives, mechanism ofconvective heat transfer with drag reduction, are also reviewed.

Integral equation methods for multiple crack problemsand related topics

2008, 38(3): 358-387. doi: 10.6052/1000-0992-2008-3-J2008-006

Abstract(2656)

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综述了平面弹性力学多裂纹问题的一些近代先进解法.一些基本解被着重提出, 它们是构成积分方程的基础.这些基本解包括由点源引起和沿裂纹线分布载荷引起.关于平面弹性力学多裂纹问题, 介绍了二类奇异积分方程, 三类Fredholm积分方程和一类超奇异积分方程.文中还研究了奇异积分方程的正则化问题, 即转化为Fredholm积分方程的方法. 为了求解上述积分方程,介绍了相应求积公式,并详细介绍求解其它众多多裂纹问题的各种方法,阐明了多裂纹解的应用.本文强调了修正复位函数这一概念的重要性, 因为它扩大了求解范围.还研究了下列多裂纹问题: (1)多半无限长裂纹问题; (2)一般载荷情况下的多裂纹问题; (3)粘合半平面情况下的多裂纹问题; (4)有限区域的多裂纹问题; (5) 圆形域多裂纹问题; (6)反平面弹性情况下的多裂纹问题; (7) 多裂纹问题中的$T$应力; (8)周期裂纹问题及其它等等. 本综述共引用了187 篇学术论文.

The introduction of application projects on mechanics of 2008

2008, 38(3): 388-389. doi: 10.6052/1000-0992-2008-3-J2008-055

Abstract(1830)

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2008, 38(3): 390-392. doi: 10.6052/1000-0992-2008-3-J2008-060

Abstract(1801)

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