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1993 Timoshenko Medal Acceptance Speech by John L. Lumley

John L. Lumley

John L. LumleyI am profoundly honored by the award of this medal. Awards like this are made, of course, not by faceless organizations, but by collections of individuals, voting in rooms which are no longer smoke-filled; it is particularly gratifying to find that so many of my colleagues think I am worthy of this honor. As Jan Achenbach remarked last year, we are of the sputnik generation, too young to have known Timoshenko, who, in fact, did have some connections with Cornell long before I came there. Although I have spent my life in fluid mechanics, I began by taking all the standard courses in solid mechanics: strength of materials, elasticity, plates and shells, buckling; in nearly every one there was a text by Timoshenko or a friend or relation, all admirably clear. I felt very grateful to him.

I would like to mention that the three ASME medal winners this year (Roger Arndt, David Crighton and I) were all together at Penn State in the Aerospace Engineering Department and the Garfield Thomas Water Tunnel, under the leadership of George Wislicenus about thirty years ago. Roger and I were on the faculty, and David came in the summers as a consultant. I think that says something about the vision and values that George used as he built his group.

I have heard a story about L. M. Milne-Thomson, whom we all know for his work on theoretical hydro- and aerodynamics. Many years ago he was asked to speak after dinner at a grand banquet in the Washington area. He may have been given an award; I am not sure. The banquet was attended by wives in elegant dresses, and there were naval officers of flag rank in class A uniforms. To everyone's surprise, he said that he wanted to give a technical lecture. After a short delay they found a tiny portable blackboard, and as he covered it with equations, he had two full admirals erasing for him in relays, tossing the eraser back and forth to each other over his head. I won't do that this evening.

Instead, I want to talk about becoming a scientist and being one, during the latter part of the twentieth century, in the United States. I realize that, when people reach my age, they think that anything they have to say is golden. I am reminded of Eric Walker, former president of Penn State. When he retired, he started writing a column in the local newspaper called "Now it's my turn". Many of us thought it had already been his turn for entirely too long, and his column was not too popular. I will try to spare you that syndrome as much as possible, but some of it is unavoidable. If the Medal Committee had any decency, they would not require a speech, and we would all be spared.

My father was an architectural engineer, and a do-it-yourself craftsman, car buff and spare-time artist. My earliest recollections are of being allowed to wash the spokes of the artillery wheels on our Hudson, while Dad polished the car with the chamois. We always had a car that was a little bit special, a little different. As we drove around Detroit, Dad would point out buildings that he had had a hand in designing or building. On Saturday mornings I remember being taken to completed buildings and building sites, and having the various flaws pointed out to me. Dad was a very demanding man; everything had to be just so. Ann Landers recently had a letter describing engineers as uncompromising, inflexible and perfectionist. That was certainly Dad. One of his friends said that Charlie was a wonderful guy, but he would hate like Hell to work for him. For years my mother talked about the dog house Dad built. It was large enough for a child to play in, with insulation and a shingled roof, and a baffle at the door to keep the cold wind out. It was a lot better built than many houses for people - certainly than the ones in Dade county in Florida. Dad never did manage to teach me how to do lettering and make arrowheads on drawings in a thoroughly professional manner, though God knows he tried. He also tried to get me always to make a complete set of drawings before I fabricated something; it never took - I always preferred to plan the project in my head, and make modifications as I went along; very unprofessional. Dad had ambiguous feelings about engineering, and from time to time thought he might have been happier as an architect. He once asked me if I was prepared to spend my life among these gray, inarticulate people. That's not entirely unfair, though I have grown rather fond of many of these people, who are only gray if you don't look beneath the surface. And there are not many, but enough poets and artists among us, so I am happy.

This is really how I got into engineering. I have always loved machinery, making things, building things. But I have spent my life as a research scientist, which is not quite the same thing. It seems that when I work on a problem, even a practical problem, I turn it into a research project; I chop it up finer and finer until there is nothing left but the fundamentals. In fact, half the theses I have supervised were experimental - a good experiment is a little closer to engineering; you usually have an opportunity to design some piece of equipment, and see it come into being. That, of course, is not quite the same as making it yourself. Evenings and weekends I restore old cars out in the barn - that satisfies the urge to make things. It also satisfies the craftsman-like desire to design in your head, with the materials and tools at hand, and modify as you go along. I get tired of too much calculation, too much precision, which I get enough of professionally. In addition, what I do professionally has a very delayed payoff - something of the order of twenty years or more. It is nice to do something that provides shorter-term gratification. It is also peaceful out in the barn.

There is less dichotomy than you might think, however, between what I do professionally and what I do evenings and weekends. I believe it was von Karman who said "There is nothing so practical as a good theory". I have always felt when constructing a very mathematical theory, that I was constructing something real and practical, to explain something physical, to make design possible. I have always been deeply offended by the attitude we meet so often, "it's just a theory", although I am certainly used to it.

More important, perhaps, I have always wanted to be involved with real things. That is, I have never wanted to abstract what I do too much, remove it too far from the real world, from the application. When I was in graduate school, it was rather nice to work on clean, neat problems that were somewhat removed from the real world. When I got my first job with George Wislicenus at Penn State, I was connected with the Garfield Thomas Water Tunnel, as well as with the Aerospace Engineering Department. The water tunnel is the world's largest high speed water tunnel, and is a part of the Applied Research Laboratory, that Penn State operates for the Naval Sea Systems Command. The Laboratory is responsible for various aspects of undersea warfare. At the Water Tunnel I was quickly immersed in the very practical problems arising from torpedoes and submarines: primarily various schemes for reduction of turbulent skin friction drag, and the many problems connected with testing in the water tunnel. At first I was a little appalled by the complex interdisciplinary problems. I had been unconsciously trained to be a bit disdainful of real problems; somehow, if you were concerned with real problems, it suggested that you didn't have the wit to find the fundamental problem underlying the real problem. It seemed that, to be socially acceptable in my circles, you never mentioned the real problem, but only the fundamental problem that you had abstracted from it. I discovered fairly fast that this was not such a straightforward matter, and that the business of reducing a real problem to a series of connected fundamental problems, all simple enough to resolve, without throwing out the baby with the bath water, was very challenging. Of course, in this reduction process you have to clip away everything that seems extraneous, hoping to be left with something that, while only a skeleton, still shares enough with the real problem to shed light on it. I think my colleagues often thought that I had pruned a bit too much, leaving a stunted stub that could not survive. However, even if they could no longer see the connection, I always saw the theoretical result as still directly connected to the real world. I also quickly came to see what a tremendously rich environment this was, how stimulating, how many problems there were to solve. I think it is a great mistake to get too far away from the applications; you dry up, you starve.

In the last few years I have managed to combine my hobby and my profession. When I was a relatively junior faculty member, I taught undergraduates. As I became more senior, however, I taught only graduate students, and for many years this was true. When I went to Cornell, I was told that I would have to teach undergraduates, but in fact I was never asked, and I never volunteered. Three years ago, however, I was made an offer I could not refuse, and I am now responsible for the undergraduate course in automotive engineering, with between fifty and one hundred students. This is one of our capstone design courses, and is a nice synthesis of much of what the kids have learned in their other courses. It is fun to teach, and I enjoy the undergraduates, although they still frighten me a bit. The young can be very judgmental and demanding. I think it helps to have raised some children. The first year I taught the course, my teaching evaluations were appalling - I hope the dean never sees them. I must say they were richly deserved. Now, however, the evaluations have substantially improved, and they no longer give me nightmares.

As I have gotten older, I have found that more and more I am a research administrator. I am sure I am not unique - this happens to all of us, but it is a bit sad. That is, I have less and less opportunity to do things myself. I am supervising others who are having all the fun. The world of science in which I live and work is structured differently now from the way it was when I was young. The world itself is changing, but of course it is also changing for me because I am getting older. The changes are also not uniform from country to country. In any event, at present, at my age, in this country, a successful scientist must have a large operation, which means a hand-full of contracts, students, post-docs, colleagues, visitors. This is a nice environment for the people working in it - I try to make it that way, recalling my earlier years. I certainly was very grateful for the environment that my thesis advisor created around us. Mostly that is simply a matter of collecting an interesting group of people, and letting them interact. I was an only child, and when I was little I became accustomed to playing by myself. Probably because of that, what attracted me to science was the pleasure of working alone at a problem uninterruptedly, following thoughts to their conclusions, trying various possibilities. I now recognize that that is not always an efficient way to work - it sometimes makes more sense to break off, and sleep on a problem, or do something unrelated, or go to the library and read something that someone else has said on the subject. That was something I never wanted to do when I was young - I didn't care what someone else had said - I wanted to do it myself. In any event, this lovely environment for everybody else is not really a nice environment for me. Whether it is desirable or not, uninterrupted work is rarely possible for me. I function in the interrupt mode, which I understand is the norm for managers. In addition, I do virtually nothing myself, but must act collaboratively with others, and at second hand. This makes me feel somewhat like a child who is forced to share his toys.

Gertrude Stein compared politicians to garbage collectors; they do necessary, but not very exciting, things that keep the place running, and are not really noticed until the system breaks down and the garbage is not collected. Administration is a lot like that, even research administration. A lot of what I do these days is the moral equivalent of garbage collection.

When I came to Cornell, of course I no longer had a connection with the water tunnel and its sophisticated but practical problems. At Cornell, I have found a certain satisfaction in being an expert witness and consultant. The problems that I solve in this capacity are reminiscent of the problems that I enjoyed resolving when I was younger. They are practical problems, usually complex and interdisciplinary, which must be broken up and abstracted to be resolved. This process involves some technology transfer, since I am often applying fundamental things that my research has taught me over the years to industrial or environmental problems.

Sometimes it is like detective work. Let me tell you about something I worked on last year, that will illustrate how a complex, interdisciplinary practical problem can lead to fundamental problems. This is in the area of atmospheric turbulence, in which I worked for some years at Penn State. Some of the material may be unfamiliar, but I think you will find the logical chain interesting. My client was a sheep farmer whose sheep seemed to be dying as a result of emissions of sulfur dioxide and hydrogen sulfide from a heavy water plant. Both sulfur dioxide and hydrogen sulfide are toxic in sufficiently high concentrations. The farmer was just a kilometer and a half from the plant, which is very close, but any normal calculations suggested that his sheep were receiving concentrations at a level considered completely safe. In addition, monitoring stations placed near his farm indicated low concentrations. I must explain how Hydrogen sulfide and sulfur dioxide happened to be emitted. Hydrogen sulfide is used in the process of making heavy water, and once a year the towers in which the heavy water is made have to be cleaned. After as much hydrogen sulfide as possible has been removed from the towers, the majority of the remainder is burned on a flare stack and converted to sulfur dioxide. The plant was right on the edge of one of the great lakes, and the stack was close to the water. After several false starts, we finally realized that the on-shore breeze from the lake, during the spring and summer, was stably stratified, and thus not turbulent, from traveling over the cooler lake water for hundreds of kilometers. The top of the stack was in this stably stratified air. Thus, the stack plume did not disperse. The cool, stable air, when it started over the warmer land, began to grow an internal turbulent boundary layer, and when this reached the height of the stack plume, the plume was sucked into the first downgoing eddy, and taken to the surface. The distances were about right so that the place where this happened was right over my client's farm, and the first descending eddy was probably caused by his cool, insulated farm buildings. His sheep were thus getting the stack plume at nearly full strength. The plume, of course, did not descend on the monitoring station. The matter was complicated by the fact that the sulfur dioxide was considerably heavier than air, and could lie on the ground in hollows among the vegetation, where the sheep would be immersed in it.

This general situation is called shoreline fumigation, and is well-known to meteorologists. However, they are only familiar with the average effects. The phenomenon of the descent of the instantaneous plume to ground level, with its associated high instantaneous concentrations, has not been measured. One of my colleagues has now submitted a proposal for laboratory measurements of instantaneous concentrations in this situation. In addition, the pooling of the sulfur dioxide at ground level, and the probability of its remaining for various periods, was a nice little fundamental problem that was fun to solve.

Everything has its down side, and I must admit I don't much like being questioned in hearings. In addition, this was all part of an environmental impact hearing in connection with a request for license renewal for the heavy water plant. When it became evident that my client had a case that would stand up, the request for license renewal was withdrawn. As a result, the outcome is moot. Also, although I work hard at communicating my results, I sometimes suspect that my clients find my name and credentials more useful to them than my findings. That's all right - at least I had fun.

Well, I hope I have kept you awake. Let me thank you again for this wonderful honor you have bestowed on me.

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