Summary of the 24th International Symposium on Shock Waves

The 24th International Symposium on Shock Waves (ISSW24) was held at the Beijing Friendship Hotel from July 11 to July 16, 2004, in Beijing, China, after a one-year delay due to the SARS outbreak in Beijing shortly before the Symposiums originally scheduled date in 2003. The event achieved success due to the continuous support and kind understanding from all the delegates and the International Advisory Committee. During the last three years, I have communicated constantly with so many people who encouraged me by providing their suggestions and advice whenever I was in need, from which I feel a sense of community: the community being full of friendship and understanding. It is very heart-warming to have such an experience and I am very happy to have served as chairman of the Symposium for such a community. On behalf of the Local Organizing Committee I would like to thank all of you for the contributions and help that you have given us, without which we would not have had the Symposium.After the announcement of the ISSW24 was sent out, the response from the international shock wave research community was very encouraging. A total of 460 abstracts were submitted to the ISSW24. Each of the abstracts was evaluated by three members of the Scientific Review Committee and the decision on acceptance was made based on the reviewers reports. 195 oral papers, including nine plenary lectures, were accepted to be presented in three parallel sessions, and 135 poster papers in three dedicated poster sessions. Topics discussed in these papers cover all aspects of shock wave research. Among the topics, supersonic and hypersonic aerodynamics; shock wave reflection, diffraction and focusing; and detonation phenomena and pulse detonation engines were the most popular. Such topics not only include interesting fundamental shock wave physics, but also have important application backgrounds. The plenary lectures of the ISSW24 were selected based on the recommendations from all the IAC members, and review the state of the art of the recent shock wave research. It was also found that a good number of papers were the result of international research collaboration. These facts have demonstrated that the ISSW24 is really international and scientific, and that shock wave research becomes an important research field of continuously increasing interest.The final programme consisted of eight plenary lectures, 123 oral papers and 75 poster papers. The total number is much smaller than that originally accepted due to the change of date, and even though this was chosen carefully, it still overlapped with other conferences, for example, the 24th International Symposium on Rarefied Gas Dynamics from July 10-14, 2004. There were 233 participants registered at ISSW24 from 20 countries and regions: Australia 9, Canada 11, China 58, France 8, Germany 14, India 21, Iran 1, Israel 7, Japan 57, Korea 2, Morocco 1, Netherlands 2, Norway 2, Russia 8, Singapore 3, South Africa 4, Chinese Taiwan 2, Thailand 1, UK 7, and USA 15.The Proceedings is a valuable resource because it brings the recent information of shock wave research together in one place, acts as an introduction to many researchers and students, and serves as a tool for promotion of the ISSW. This is the reason why the Local Organizing Committee works hard to manage to publish it. Two hundred and six papers in total are published in the final proceedings and are organized in such a way that all the papers relating to similar topics are grouped together. Both oral and poster papers are considered to be equal without making any distinction between them. The Proceedings are more comprehensive than the CD-ROM that all the participants received during the Symposium, which only contains the full papers that were received before June 15, 2004, and was intended as a tool for the prompt exchange of research information.The ISSW24 was delayed one year because of the SARS outbreak in Beijing last year. In keeping with the pattern set at the ISSW over the last 40 years, the International Advisory Committee of the ISSW24 has decided that the ISSW25 will be held in the year 2005. The organizer of the ISSW25 has been chosen by voting of all the IAC members at the end of the year 2002 to gain more time for the next organizer. Prof. K. P. J. Reddy from Indian Institute of Science has been selected to be the Chairman of the ISSW25. I sincerely express my congratulations to him and wish ISSW25 a success.We were greatly assisted in planning the ISSW24 by continuous support from various sponsors: the Chinese Academy of Sciences, the Nature Sciences Foundation of China, the Chinese Society of Shock Waves, the Chinese Society of Theoretical and Applied Mechanics and the Chinese Society of Aerodynamics. On behalf of the Local Organizing Committee, I would like thank all members of the International Advisory Committee for their guidance and suggestions, and the Scientific Review Committee for their careful and efficient evaluation of the abstracts. My greatest thanks have to be to the delegates for providing high quality papers and actively participating in the Symposium. For editorial assistance, I wish to thank Dr. C. Wang for re-editing all the papers according to the required style of the ISSW24, and for compiling these proceedings. I must also thank Miss Q. Pu and X. Wang, my secretaries, for taking care of so many details in organizing the Symposium. Many thanks also go to the staff and students of the Key Laboratory of High Temperature Gas Dynamics, the Institute of Mechanics, Chinese Academy of Sciences for helping and supporting me over the past three years. Finally, I want to express my appreciation to Dr. Chris Caron from Springer-Verlag for his kind cooperation in publishing these proceedings.Received: 30 November 2004, Accepted: 30 November 2004, Published online: 24 February 2005[/PUBLISHED]Zonglin Jiang: Chairman of the ISS24Correspondence to: Zonglin Jiang     

In memoriam Professor Richard Douglas Archer (1925-2004)

Richard Douglas Archer, (Doug), born in Melbourne on 3/4/1925, passed away on 8/8/2004 after a short illness. Doug had a diverse career in the academic, aeronautical and shock wave areas over a very long period, remaining active in all these until suffering a stroke three years ago.His career began with his enrolment in a physics degree programme at Melbourne University in 1943. Due to the wartime pressures, he completed the three year bachelors degree in two years, specializing in radio physics. He then served in the RAAF (Australian air force) as a radar engineer until 1946. On demobilization, his interest in aviation led him to undertake a Bachelor of Engineering (Aeronautical) at Sydney University which he completed in 1949. He was awarded a Fulbright scholarship for further study in the USA, which he undertook at the University of Minnesota, completing a Masters in Aeronautical Engineering from 1950 to 1952. University of Minnesota had at that time the Rosemount Aerodynamic Laboratory, which was one of the major aeronautical research facilities in the USA. During this period he toured the length and breadth of the USA in his 1939 Chevrolet, at times working at building grain silos, making Turkish sandwiches and, of course, as a teaching assistant at the University. Upon completing his degree, Doug traveled to the UK where he worked with the aerodynamic and wind tunnel group at the Handley Page aircraft company in London.On returning to Australia in 1953, he was employed with the Commonwealth Aircraft Corporation (CAC), becoming involved in many projects including supersonic interceptor aircraft design. In 1954, while still with the CAC, he obtained an additional position as a part-time lecturer at RMIT (now RMIT University). Realizing that his preferred career lay in teaching, he moved to a full time position at RMIT as Senior Lecturer in charge of Aeronautical Engineering in 1957. Further study was still attractive to him and, in 1959 he returned to the Rosemount Laboratory to undertake a PhD, which he completed in 1963. Here he was involved in wind tunnel testing of supersonic re-entry vehicles. He returned to a post as the aerodynamic specialist for the Aeronautical Engineering degree at the University of NSW which was then a group embedded in the School of Mechanical and Industrial Engineering. Within a short period, he became the Head of this group, a position he occupied with great distinction for over a quarter of a century until his retirement in 1990.His leadership of this group resulted in the development of both the Aeronautical Engineering course and the Aerodynamics laboratory which became noted for the range and quality of its equipment. He undertook the largest teaching and supervision load in the School and was greatly respected by students because of his empathy with them. He introduced many new undergraduate subjects in Aeronautical Engineering and was responsible for the development of the higher degree subjects in all areas of the School for many years.His initial research projects at the University of NSW were a continuation of his studies in the USA and were oriented towards a numerical assessment of the re-entry vehicle problems. In 1967, he initiated a new experimental project on shock wave focusing. While later diversifying into many other experimental shock wave projects, he always retained an interest in this area. Only recently, after his initial stroke, he proposed new studies on the potential damage to human brains from wave focusing at the rear from repeated small impacts from the front, such as with soccer players. In 1991, shortly after his retirement, he spent a period with Professor Takayama in Japan to learn more about the bioengineering applications of shock waves.He also developed many new research projects with both an international and an Australian orientation. These included studies of very low speed flight (related to agricultural aircraft), man powered and flapping wing flight. He was one of the pioneers of this last area with particular emphasis on the basic physics of bird flight. In addition, he examined the use of aircraft to create shock waves for the extinction of bushfires, he had a strong interest in engines, particularly those for aircraft and he published a comprehensive text on aerospace propulsion. He undertook a large study on light aircraft accidents in Australia which identified areas on concern where the rates are high. He was prominent in the Australian branch of the Royal Aeronautical Society, acting as a committee member and president for a many years.Internationally, he was best known for his work with shock waves. He attended his first meeting of the International Shock Wave Symposia in 1969 and missed few of the biennial meetings from then until his illness in 1999. He was highly respected in this community, not only for his papers and his careful questions, comments and discussion but because he was above all, a natural gentleman. Doug is survived by his wife Olga, who he married in 1959 and his three sons, Robin (born in the USA while Doug was studying for his PhD), Mark and John.Published online: 18 February 2005[/PUBLISHED]     

Resonance-behavior of non-linear one-dimensional gas vibrations analyzed by the Ritz-Galerkin method

Summary The present paper concerns an approximate analysis of damped resonance vibrations in a closed cylindrical pipe with harmonic excitation at one pipe end. Earlier experiments made by Lettau have disclosed that such vibrations may be highly non-linear and may even include shock waves travelling back and forth. The analysis is based essentially on the socalled Ritz-Galerkin method. Emphasis is put on the mechanism of the analysis rather than on a strict mathematical justification hereof. The theoretical results are in close agreement with the experimental evidence. Further a criterion for the presence and absence of shocks is derived.The present investigation was undertaken while the author, on leave from the Technical University of Denmark, was working as a Research Associate ar Stanford University in California on a Research Fellowship from International Cooperation Administration, Washington D. C. Thanks are due to all these institutions.In particular the author wishes to express his sincere thanks to Professor K. Klotter, Division of Engineering Mechanics, Stanford University, for his kind encouragement of the work and valuable criticism.     

In memoriam Professor A. G. Gaydon F.R.S. (1911-2004)

I, a starting post-graduate in 1958, first met Dick Gaydon in the basement area of the Chemical Engineering Department of Imperial College where the nonchemical engineers were exiled. It was sometime later, when I suggested to my employers, the Central Electricity Research Laboratories, that they should produce sufficiently handsome funding for me to build and operate a shock tube. They agreed, but on condition that Dick become a consultant and keep an eye on my progress. For some years my colleagues, Bob Stirling and Sammy Sloan, and I received monthly visits.Some will have already read obituaries and additional tributes in the daily press and combustion journals. There, all have paid full regard to his outstanding contributions as one of the 20th centurys supreme spectroscopists, particularly in his accurate determination of the dissociation energy of nitrogen, with its implications for the correct forecasting of the strengths of blasts from explosions of atomic weapons. Whilst his great love in science concerned experimental spectroscopy, he devoted much effort to the development of various techniques to excite radiation. Principal amongst these were flames produced by novel types of burner and gases heated and compressed in shock tubes.Many will be familiar with his six books, some written in collaboration with colleagues such as Pearce on spectroscopy, Wolfhard on flames and Hurle on shock tubes. That on flames, together with the text by Lewis and von Elbe, formed the principal wells of information from the 1960s to the 1990s, with the former running to three completely revised editions over a couple of decades. Indubitably, the Gaydon and Hurle monograph will be most familiar to subscribers to Shock Waves. It was one of a number on shock waves published in the 1960s, e.g., Soloukhin, Bradley and Tonnies and Green. My feeling is that the Gaydon and Hurle monograph answered more experimental problems than did the others.Whilst continuing to be somewhat isolated from the chemical engineering interests of the department, he had over his career at Imperial College a wide range of physicists and chemists, both from this country and abroad, occupying post-graduate and post-doctoral positions, many of whom went on to highly distinguished scientific careers. All in all they contributed some 150 scientific papers of high merit to the most eminent of journals.Dick had many friends and collaborators worldwide. As with most of the Western World, he was highly disturbed by the USSR invasion of Hungary and, although much troubled by his conscience, gave up correspondence with long established friends amongst Russian scientists. It was some time before he rehabilitated these.He always regarded himself as an experimentalist. As the most modest of men, he would never have regarded himself as a brilliant one, though all his colleagues did. He was elected to the Royal Society, possibly in more harmonious times, in 1953. Dick was also the kindest of men. I can still recall his questioning which attempted to avoid causing hurt to presenters of contentious papers: so politely were these framed that the authors frequently remained completely unaware of the dismantling of the foundations of their case. I have often wondered how they felt when the penny eventually dropped.He had an abiding passion for butterflies and moths and travelled the world taking photographs of them. No easy task for somebody who lost the sight of one eye through an explosion of peroxide of diethyl ether, when purifying the ether itself, early in his career. When travel proved too much for him a pet dog took their place in his affections.Published online: 18 February 2005[/PUBLISHED]     

Professor T. C. Papanastasiou's contributions to rheology and computational fluid mechanics

Professor T. C. Papanastasiou's contributions to rheology and computational fluid mechanics are numerous and have a lasting effect. In the short span of a professional career of about 10 years, and in such diverse places as the University of Minnesota, the University of Michigan, and the Aristotle University of Thessaloniki, he developed and implemented new ideas in the fields of rheology and computational fluid mechanics. He dealt with such important topics as: i) modelling of viscoelasticity and viscoplasticity through appropriate constitutive equations; ii) numerical techniques based on the finite element method, streamline integration, inverse of the unknown, and Newton iteration for integral-differential equations; iii) numerical simulation of important polymer processes, such as fiber spinning, film blowing, film casting, extrusion and coextrusion of polymeric liquids; iv) stability analysis of multiple flows; v) three-dimensional computational techniques for generalized Newtonian flows; vi) numerical analysis of viscoplastic flows; vii) solidification problems; viii) outflow boundary conditions, etc.His many contributions include authoring two books in the area of fluid mechanics, one for undergraduate and the other for graduate use. He was a mentor and an advisor to a dozen people, his former students, who have, in their own right, successful careers, some as professors, others as research engineers in major industries. The ideas and foundations of his work are currently pursued and studied by many researchers world-wide, and in this manner it is the most appropriate tribute to him and a guarantee that his name will be remembered for years to come.Dedicated to the memory of Professor Tasos C. Papanastasiou     

Editorial

On behalf of the board of editors of the journal Shock Waves, I am pleased to give a brief overview of recent shock wave research activities. Shock waves are comprehensive representations of phenomena that appear in non-linear wave dynamics. Historically, shock wave phenomena started to be intensively investigated with the advent of high-speed gas-dynamics and these investigations are nowadays supported by the development of both super-computation and advanced experimental technology. Meanwhile, shock wave research has been expanding its scope to various interdisciplinary applications. A particular case is shock wave research in condensed matter which has a history as long as that of corresponding research in the field of gas-dynamics. However, although there are many dynamic similarities between shock wave motion in gases and condensed matter, the difference with respect to physical properties of both media was so dominating that for a long time research activities in these two fields have been regrettably rather isolated with only little communication between both scientific communities. Realizing that many methodologies are increasingly overlapping, it is now a good time for all of us - in the spirit of the advancement of science and technology - to try to look at shock wave phenomena in various media in order to understand their common features. The sheer variety of multi-faceted applications in shock wave research are reflected by an impressive number of international meetings such as the International Symposium on Shock Waves, the International Colloquium on the Dynamics of Explosions and Reactive Systems and the Conference on Shock Compression of Condensed Matter. In addition to these major international activities, many countries regularly organize national shock wave symposia. As a result of such activities the Asia-Pacific Shock Wave Research Society was established in 2003, whose wide membership includes researchers from the Asia-Pacific region and beyond. On the occasion of assuming the position as new Editor-in-Chief of the journal Shock Waves, I would like to thank my predecessor, Prof. Hans Grönig, for the many years of effort devoted to this task. I will continue to promote this journal as a major publishing platform that supports all international and interdisciplinary shock wave research activities and provides readers with an invaluable source of information.     

Improvement of chemical kinetic data at high temperatures by piston actuated shock tube,excimer laser photolysis,and atomic resonance absorption spectrometry

Qualitative improvement of chemical kinetic data at high temperatures has been achieved, to a great extent, by use of a combination of the piston actuated shock tube, the excimer laser photolysis, and the atomic resonance absorption spectrometry. Some of the important studies on elementary reactions performed recently in the University of Tokyo are demonstrated.This article was processed using Springer-Verlag T_EX Shock Waves macro package 1.0 and the AMS fonts, developed by the American Mathematical Society.     

Shock tube kinetics in homogeneous and heterogeneous reaction systems

The shock tube used as a high-temperature wave reactor has dominated high-temperature kinetics for more than 45 years. The nearly instantaneous heating to high temperatures, the accessible wide temperature and pressure ranges, and the diffusion-free reaction conditions are the main advantages of this technique for measuring rate co-efficients at high temperatures. In this paper some applications of the shock tube technique for kinetic studies in homogeneous and heterogeneous reaction systems will be discussed. The examples to be presented were obtained in the author's laboratory. They include thermally and photolytically induced chemical reactions, which were studied by applying different optical absorption techniques.An abridged version of this paper was presented as Paul Vieille Memoiral Lecture at the 20th International Symposium on Shock Waves, CALTECH, Pasadena 1995.     

我国航空航天结构强度事业的开拓者——黄玉珊

黄玉珊先生是我国著名的力学家、航空航天科学家,新中国航空高等教育的奠基人.他不满14岁考入大学,不满23岁时师从国际著名力学大师铁摩辛柯获博士学位,随即义无反顾地回到战火连绵的祖国,受聘中央大学教授.新中国成立后,面对航空工业初建时期技术基础薄弱、人才储备不足、教育体系不完善的困境,他呕心沥血,鞠躬尽瘁,建立新学科,开创新局面,毕生致力于祖国航空航天教育和科技事业.他被认为是我国旧飞机疲劳定寿和延寿、损伤容限评定和新飞机损伤容限设计最早的创始人之一,也是我国飞机自激励振动研究和航天结构环境强度事业的开拓者.本文通过回顾黄玉珊先生在固体力学、航空航天结构强度领域的主要学术成果和卓越贡献,缅怀其坚定不移的报国情怀、严谨求实的治学态度、勇于开拓的创新精神、高瞻远瞩的学术视野以及求真务实的教育思想.     

Heat flux measurement over a cone in a shock tube flow

This paper is the part 2 of our previous thin film heat transfer measurements. In the first report we measured time variations of heat flux over a cylinder placed in a shock tube flow and compared experimental results with CFD results, Saito et al. (Shock Waves 14:327–333, 2004). We report a result of heat transfer measurements over an 86° apex angle cone surface impinged by a Ms = 2.38 shock wave in air with distributed thin film transfer gauges along cone surface and its comparison with results of numerical simulations. We performed double exposure holographic interferometric observation, and also from the heat transfer measurement and numerical simulation, confirmed the presence of delayed transition from regular to Mach reflection over the cone. The numerical estimation of delayed transition distance from the apex agreed very well with experimental one.      

Effect of yaw on the starting point of curvature for reflected diffracted shock wave (subsonic and sonic cases)

Lighthill (Proc. R. Soc. A 198, 454–470, 1949) considered the diffraction of a normal shock wave passing over a small bend. The bend being small Lighthill was able to linearize the flow equations and solved the problem through several mathematical techniques. Following Lighthill (Proc. R. Soc. A 198, 454–470, 1949), Srivastava and Chopra (J. Fluid Mech. 40, 821–831, 1970) extended the work to the diffraction of oblique shock waves. Srivastava (AIAAJ 33, 2230–2231, 1995) considered the problem of starting point of curvature and extended the work to yawed wedges (Srivastava in Proceedings of the 14th International Mach reflection symposium Sun Marina Hotel, Yonezawa, Japan, 1–5 October 2000, pp. 225–249, 2002). Srivastava (Shock waves 13, 323–326, 2003) considered the problem for starting point of curvature when the relative outflow behind reflected shock before diffraction has been subsonic and sonic. The present work is an extension of the work published in Srivastava (Shock waves 13, 323–326, 2003) when the wedge has been yawed through an angle. The results have been obtained for two angles χ = 60° and χ = 40° (χ is the angle of yaw).      

Experimental and numerical study of pressure wave refrigerator performance

A new compact pressure wave refrigerator has been designed and manufactured at the Shock Wave Research Center, Institute of Fluid Science, Tohoku University. The performance of this device was investigated for combinations of major operational parameters, such as the rotational speed of gas distributor, the length of expansion tubes, the input gas pressure. The maximum temperature decrease of 20 K has been measured. Some theoretical consideration to the efficiency of the pressure wave refrigerator and two-dimensional numerical simulations were carried out in order to understand the wave interactions that take place inside the device.Received: 26 May 2003, Accepted: 12 August 2003, Published online: 14 October 2003 Correspondence to: T. Saito     

In memoriam Dr. Werner Heilig (1933-2003)

A dear friend and colleague, Dr. Werner Heilig, died last December (2-12-2003) after a short and painful illness. Dr. Heilig was well known and respected in the world-wide shock wave family due to his contributions to our understanding of shock reflection and interaction phenomena.Dr. Werner Heilig was born in Freiburg in January 1933. He received his matriculation from the Kepler-Gymnasium in Freiburg in 1953 and immediately thereafter started studying Mathematics and Physics at the Albert-Ludwigs University in Freiburg, from which he graduated in early 1958. After graduation he took an extra two years of pedagogy studies in order to qualify as a teacher of mathematics in a high school (Gymnasium), and indeed he served as a mathematics teacher in a Gymnasium from January 1961 until March 1964. A big change in his professional career took place in April 1964 when he joined the Ernst-Mach-Institute in Freiburg. Simultaneously with his new work at the Ernst-Mach-Institute he was teaching every morning from 8 to 9 oclock mathematics at the St. Ursula Gymnasium, walking to his new place of work immediately after teaching. At that time he also started his PhD studies at the University of Karlsruhe. The title of his thesis was: Theoretical and experimental studies of shock wave interaction with a sphere and a cylinder (Theoretische und experimentelle Untersuchungen zur Beugung von Stosswellen an Kugeln und Zylindern). Dr. Heilig continued this investigation, as well as other related topics, throughout his professional career. His PhD research was co-supervised by Professors Zierep and Oertel and the degree was granted in July 1969. In his dissertation he also discussed the transition criteria from regular to Mach reflection for shock wave reflection from wedges or cylinders (as is evident from Fig. 13 in his dissertation). However, since his results were not published in a reviewed journal, he has not received the credit he duly deserved.After receiving his PhD degree, Dr. Heilig started building his reputation as a careful and reliable researcher in gas dynamics, focusing his attention on shock wave reflection from wedges, shock and blast wave propagation in ducts and tunnels, and shock wave interaction with boundaries of various shapes. Until the mid 1980s most of his work was experimental, that being the strong side of the Ernst-Mach-Institute at the time. In early 1984 Dr. Heilig was assigned to introduce CFD to the Ernst-Mach-Institute. This move forced him to go from being an experimentalist to a CFD researcher, which proved to be very demanding. However, Dr. Heilig did it well, relying on his mathematical skills earned as a student in the 1950s. From the mid 1980s on he was the head of the gas dynamics group at the Ernst-Mach-Institute, and in January 1997 he became the vice-director of the Ernst-Mach-Institute, a position he held until his retirement in February 1998. Once free from formal obligations, he avidly continued his research activities, submitting proposals for (and receiving) research contracts, and writing the chapter on shock wave propagation in ducts and tunnels in the Handbook of Shock Waves which was published in 2000 by Academic Press.I first met Dr. Heilig when he attended the 12th Shock Waves Symposium, which was held in Jerusalem in July 1979, and we kept in touch ever since. We jointly proposed and conducted research on various aspects of shock wave interaction with bodies of numerous shapes, and co-authored several papers based on the results of our joint-research. It was a pleasure working with Dr. Heilig; he was a very careful scientist who was never fazed by challenging problems. His untimely death has shocked and saddened us all. May the emptiness left in our hearts by his departure be filled by gentle memories of Dr. Werner Heilig, an outstanding researcher, colleague and friend.Published online: 18 February 2005[/PUBLISHED]     

Monte Carlo analysis of dissociation and recombination behind strong shock waves in nitrogen

Computations are presented for the relaxation zone behind strong, one-dimensional shock waves in nitrogen. The analysis is performed with the direct simulation Monte Carlo method (DSMC). The DSMC code is vectorized for efficient use on a supercomputer. The code simulates translational, rotational and vibrational energy exchange and dissociative and recombinative chemical reactions. A new model is proposed for the treatment of three body recombination collisions in the DSMC technique which usually simulates binary collision events. The new model represents improvement over previous models in that it can be employed with a large range of chemical rate data, does not introduce into the flow field troublesome pairs of atoms which may recombine upon further collision (pseudo-particles) and is compatible with the vectorized code. The computational results are compared with existing experimental data. It is shown that the derivation of chemical rate coefficients must account for the degree of vibrational nonequilibrium in the flow. A nonequilibrium chemistry model is employed together with equilibrium rate data to compute successfully the flow in several different nitrogen shock waves.This article was processed using Springer-Verlag T_EX Shock Waves macro package 1990.     

石灰岩中核爆冲击震动效应的化爆模拟

根据爆炸能量相似律,提出了采用化爆模拟核爆在石灰岩中爆炸的冲击震动效应的方法。通过对核爆和化爆分别在石灰岩中爆炸的冲击震动效应的分析,建立了化爆与核爆之间自由场峰值应力和峰值速度的模拟关系式,并利用最小二乘法,拟合出了最终的模拟表达式。经过对关系式的计算表明:拟合出的关系式较可靠,在已知化爆的基础上可近似计算核爆的峰值应力及峰值速度。     

Interaction of a normal shock wave with a compressible turbulent flow

A speckle photographic method, which is sensitive to changes of gradients in fluid density, is applied for analyzing a compressible turbulent air flow with density fluctuations. Spatial correlation coefficients, turbulent length scales, and energy spectra are determined under the assumption of homogeneous isotropic turbulence. The experiments are performed in a shock tube where the flow is passed through a turbulence grid. Measurements are taken before and after the turbulent regime interacts with the normal shock wave reflected from the tube's end wall. Amplification of the turbulence intensity by the shock interaction process is verified quantitatively and is shown to be restricted to the lower wave numbers in the spectrum.A version of this paper was presented at the 11th Symposium on Turbulence, University of Missouri-Rolla, Oct. 17–19, 1988.To Professor Dr.-Ing. Klaus Gersten on the occasion of his 60th birthday     

Shock wave diffraction over a 90 degree sharp corner — Posters presented at 18th ISSW

A special poster session was run during the 18th International Symposium on Shock Waves, held on July 21 – 26, 1991, in Sendai, Japan. The purpose of this session was to compare various CFD schemes which are useful for simulating shock wave phenomena. A 2-D planar shock wave diffraction over a 90 degree sharp corner was selected as a bench mark problem. The problem specification and the output format are described below. Experimental outputs for the close flow conditions to the computational ones were also called for. Twenty six poster presentations were made at this session and the majority of the posters reflected a standard of excellence that warrants publication in the Shock Waves journal. Therefore these results are reproduced here. However, since there is a limit on the available page numbers, it was not possible to publish all the posters that were presented at the special poster session. We express our sincere thanks to all the participants in this session.     

Recent advances in shock tube/laser diagnostic methods for improved chemical kinetics measurements

Shock tubes combined with laser diagnostics provide state-of-the-art capabilities for studying the chemical kinetics of combustion processes. We report here several new concepts and methods designed to improve shock tube performance and modeling, extend shock tube operating regimes, provide access to low vapor pressure fuels, and quantitatively measure species time-histories using continuous wave laser absorption. These new methods are discussed in the context of studying ignition processes of hydrocarbon fuels at practical engine conditions; examples of the use of these methods to study the chemical kinetics of real fuels and to resolve current issues related to shock tube facility effects are given.      

A Kolsky bar: Tension,tension-tension

The present paper introduces a new technique which combines rotation disk and traditional Kolsky bar (often termed as split-Hopkinson bar). This technique can be employed to study the tension stress-strain relations and tension-unloading-tension strain-rate history effects of materials in the strain rate range from 10²–10³s⁻¹. The rise time of the incident wave is as short as 15 μs because of the particular design. An attempt is made to estimate strain error caused by the thread connection between the specimen and the bars, and stress error due to the mismatch of the cross section of the specimen and bars. A short rise-time incident wave appears to be most advantageous in view of maintaining the accuracy of the stress-strain curve obtained near the initiation. Preliminary tests are performed on the instrument. Comments are made for this design configuration. M. Li (Student Member of SEM), presently at the Department of Aerospace Engineering, Mechanics and Engineering Science, University of Florida, Gainesville, FL 32611, was Research Associate; R. Wang (formerly A.J. Wang) is Professor; and M.-B. Han is Associate Professor, Department of Mechanics, Peking University, Beijing 100871, P.R. China.