Kárm

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Kármán, Theodore von

(b. Budapest, Hungary, 11 May 1881; d. Aachen, Germany, 7 May 1963)

aerodynamics.

Theodore (in Hungarian, todor) von Kármán was the son nof Maurice (Mór) Kármán, a university professor of education who was knighted by Francis Joseph of Austria-Hungary in 1907 for reorganizing Hungarian secondary education, and Helen Konn, descendant of a distinguished Bohemian-Jewish family. The third of four sons, he also had a younger sister, Josephine (Pipö), to whom he remained devoted until her death in 1951. Having attended the Minta, a model Budapest Gymnasium organized according to his father’s ideas, Kármán won the Eötvös Prize for Hungarian secondary students in science and mathematics before entering the Palatine Joseph Polytechinic (now the Technical University of Budapest), where he first became interested in developing a theoretical basis for the solution of problems in mechanics. After a year of compulsory military service as an artillery cadet, he spent three years as an instructor at the Palatine Joseph.

In 1906 Kármán received a two-year fellowship for postgraduate work from the Hungarian Academy of Sciences and decided to go to Göttingen, wheere he worked with Ludwig Prandtl, the “father of aerodynamics” and only six years Kármán’s senior; he also came under the influence of the great mathematicians David Hilbert and Felix Klein. Apart from short terms at Berln and Paris, Kármán remained at Göttingen for six years, serving as privatdocent during the last three. Besides working in aerodynamics, he collabporated with Max Born in an attempt to explain the temperature dependence of specific heat. Their theory, based on the assumption that atoms were arranged in a regular lattice, proved to be more general than the theory of atomic heats of Peter Debye, which was published first. (Both Born and Debye later received Nobel prizes.) Göttingen also pioneered some of the ideas that later became crucial to the development of technical education, notably that engineering and other apoplied sciences must rest firmly on a scientific foundation if they are to advance other than by trial and error—a viewpoint that Kármán defended throughout his long career.

Before leaving Göttingen, Kármán attracted con-siderable attention with his first important work, the elucidation of a phenomenon that had been observed by others (notably Henri Bernard) but had not been previously analyzed. He found that when a fluid flows at a velocity V past a cylindrical obstacle of diameter d at right angle to the axis of the cylinder, a separation of the wake into two rows of periodic vortices ioccurs, alteernating in positioin between the two sides like street lights. The phenomenon is known as the Kármán vortex street (or “Karmansche Wirbelstrasse”) or simply Kármán vortices. It leads to selfinduced vibrations at a frequency n=0.207 V/d cycles per second that can build up to destrructively large

magnitudes when a structure designed on the basis of static considerations is subjected to dynamic conditions, as in aircraft wing flutter or the behavior of a bridge in a high wind. (The failure of the first suspension bridge across the Tacoma Narrows at Puget Sound, Washington, in a fresh gale in 1940 was later shown by Kármán to have been caused by Kàrmàn vortices created when the wind reached a velocity of V = 42 miles per hour.)

After a term of teaching at a mining college in Schemnitz (now Baňská Štiavnica) in Slovakia, under conditions that were not conducive to a research career, Kàrmàn returned to Göttingen and presently secured a professorship at the Technishce Hochschule in Aachen, where he remained (except for military service during World War I) until 1929. There he became heavily involved in the development of aviation.

Kármán’s interest in flying dated back to a demonstration he observed in Paris in 1908. In World War I he was assigned to the nascent Austro-Hungarian air force and worked on problems relating to propeller design, synchronized guns, and fire protection of fuel tanks. He also experimented with helicopters and demonstrated the superiority of two counterrotating propellers from the viewpoints of vibration and control. When he returned to Aachen after the war, he became interested in helping the students design glider planes, little realizing that he was laying the foundations of a new German air force, the Luftwaffe of World War II. He counted such pioneers as Hugo Junkers, Ernst Heinkel, and A. H. G. Fokker among his friends and associates.

Kármán’s most important contribution stemming from this period was a new law of turbulence, a field in which he continued a friendly rivalry with his former mentor Prandtl, still at Göttingen. Once again, the underlying mathematical theory proved to be of considerable practical importance, not only in aeronautical engineering (in predicting drag on the surface of aircraft and—later—rockets) but also in describing flow through pipes, an aspect of his research of great benefit to the oil industry and to other hydraulics applications.

During 1926–1927 Kármán made an extensive trip to the United States and Japan. In the United States he spent some time at the California Institute of Technology in Pasadena, where a new aeronautics laboratory had been endowed by Daniel Guggenheim; while in Japan, he helped to modernize the Kawanishi Company in Kobe, for which he designed a new wind tunnel. Soon after his return to Aachen, Kármán received an offer to become the director of the Guggenheim Aeronautical Laboratory from Caltech’s cheif, R. A. Millikan, and accepted. He left Aachen at the end of 1929.

Kármán’s long tenure at Caltech saw its emergence as one of the top aeronautical research centers in the world. But perhaps even more important were his contributions to the teaching of aeronautical engineering, which he put on a scientific (especially mathematical) basis and which he greatly extended in scope to postgraduate and postdoctoral studies. A substantial number of professorial chairs in aeronautics in the United States and in other countries came to be occupied by Kármán’s students. One such student was Hsue-shen Tsien, an extraordinarily talented engineer from Shanghai, who later taught at the Massachusetts Institute of Technology and at Caltech, before falling under false suspicion during the anti-Communist crusades led by Senator Joseph McCarthy. Tsien ultimately returned to China, where he achieved a high position and contributed substantially to that nation’s technological development. Another of Kármán’s students was Francis H. Clauser, later a well-known aircraft designer (DC-6) and engineering educator.

Kármán’s presence at Caltech also played a part in the development of the aircraft (and later space) industry in southern California. He helped to found the Aerojet Engineering Corporation, which later (after Kármán had liquidated his interest in it) grew into one of the industrial giants of the jet age, as Aerojet-General Corporation, a subsidiary of the General Tire and Rubber Company.

Another development deriving from Kármán’s activities was the organization of the institute’s Jet Propulsion Laboratory (JPL), a government-funded center of rocket research and space communications techniques that is acknowledged as a principal contributor to America’s preeminence in space technology. Originally concerned primarily with rocket research arising from military requirements during and after World War II, the laboratory was greatly expanded after the United States entered the field of space exploration and shifted its emphasis to pro pellants and to remote control; but the aerodynamics research started by Kà;rmà;n remained a concern of the laboratory throughout.

At Caltech, Kármán and his students laid the foundations for aerodynamic design leading to supersonic flight, an area that at one point appeared to be stymied by vehicle-design (rather than propellant or engine) considerations. At the same time Kármán continued to be a valued consultant of the U.S. Air Force and played a part in its emergence from a subsidiary position as a branch of the U.S. Army to autonomous statues. He was chairman of a committee that produced the report Toward New Horizons, which became the blueprint for the new air force; he subsequently served on the force’s scientific advisory board. In addition, he had a hand in the organization of the Rand Corporation, the first of the “think tanks” or quasi-independent civilian research organizations that work under contract to a government department.

When the North Atlantic Treaty Organization (NATO) was organized in 1949, Kármán proposed the organization of the Advisory Group for Aeronautical Research and Development (AGARD) to review aeronautical advances, exchange information among the treaty members, and generally help solve defense problems of mutual interest. Under his leadership the terms of reference of AGARD were very broadly interpreted and led to the establishment of the international aerodynamics school known as the Training Center for Experimental Aerodynamics (later named the Von Káumán Center). He also played an important part in the formation of the Advanced Research Projects Agency of the U.S. Department of Defense.

Kármáns’s multiple roles as aeronautical engineer, university professor, and industrial and government consultant brought him frequently to public notice, a role that he did not seek. After the Nazi government took over the Junkers firm in Germany, it was discovered that some American aircraft manufacturers were infringing inventions belonging to Junkers, which resulted in a patent suit in a United States court. Although Jewish, Kármán testified in support of the Junkers contention, which many thought was carrying scientific detachment too far. He protested vigorously when Hsue-shen Tsien was persecuted for alleged Communist ties, placed under a deportation order, and then detained for five years, presumably to allow his knowledge of secret projects to become obsolete.

Kármán remained quite unabashed about his lifelong association with military authorities, first in Austria-Hungary, then in Germany, and finally in the United States and NATO. His viewpoint was that of an engineer of an earlier era who may be considered to have discharged his debt to society once he has contrived to “provide an analysis of what would happen if certain things were done”; he thought that “scientists as a group should not try to force or even persuade the government to follow their decisions.”

Kármán never married. His sister Pipö, first with their mother and then alone, managed his household in Aachen and in Pasadena. He died at the home of his close friend Bärbel Talbot, widow of the Aachen manufacturer Georg Talbot.

Kármán received many honorary degrees and medals, including the U.S. Medal for Merit (1946), the Franklin Gold Medal (1948), and the National Medal of Science (from President Kennedy, 1963), as well as most awards given in aeronautics and fluid mechanics. He was a commander of the French Legion of Honor, a member of the Pontifical Academy of Science, and the recipient of similar decorations from Germany, Greece, Spain, and the Netherlands.

Despite his many public activities, he never became a great public figure in the way of many inventors, perhaps because theoretical aerodynamics is not a very accessible field to the layman; nevertheless, his work in that field and in rocket research had helped shape both scientific and political history.

BIBLIOGRAPHY

I. Original Works. Kármán was the author or coauthor of 171 papers and articles. His five books are General Aerodynamic Theory, 2 vols. (Berlin, 1924), written with J. M. Burgers; Mathematical Methods in Engineering (New York, 1940), written with M. A. Biot, translated into French, Spanish, Portuguese, Italian, Turkish, Japanese, polish, and Russian; Aerodynamics: Selected Topics in Light of Their Historical Development (New York, 1954), translated into Spanish, Italian, German, French, and Japanese; and From Low-speed Aerodynamics to Astronautics (London, 1961). For his other publications, see the four-volume Collected Works of Dr. Theodore von Kármán (London, 1956), which contains the papers published until then; a complete bibliography, including twenty-five later papers, appears, in his biography (see below).

II. Secondary Literature. In his late seventies, Kármán contracted with a journalist, Lee Edson, to publish an autobiography contrived from dictation and taped interviews. The work was about three-quarters finished when Kármán died, but the U.S. Air Force underwrote its completion and it was ultimately published as The Wind and Beyound: Theodore von Kármán, Pioneer in Aviation and Pathfinder in Space (New York, 1967). It is largely a personal biography, which mentions Kánmán’s scientific work only in passing, but it does contain a complete bibliography of his writings and a list of his degrees, decorations, and awards. Successive bibliographies also appear in Poggendorff, V, 612; VI, 1282; and VIIa, 692–693.

Charles SÜsskind

Complete Dictionary of Scientific Biography

Theodore von Kármán

views updated May 23 2018

Theodore von Kármán

The Hungarian-born American physicist Theodore von Kármán (1881-1963) made significant contributions to the fields of hydrodynamics, aerodynamics, and thermodynamics.

Theodore von Kármán was born on May 11, 1881, in Budapest. His father, a professor of education, founded the Minta Model Gymnasium, where Theodore was enrolled at the age of 9. There he learned the inductive reasoning approach which he practiced all his life. In 1898 he entered the Royal Joseph University of Polytechnics and Economics in Budapest, the only engineering school in Hungary, graduating with distinction in 1902. He served in the Austro-Hungarian Army for a year and then returned to the Royal Joseph as assistant professor.

Professional Accomplishments

Von Kármán's first major contribution to the study of engineering materials was the extension of the Euler theory of elastic-column buckling to an explanation of inelastic buckling (published 1906). That same year Von Kármán was granted a 2-year fellowship to study at the University of Göttingen under the famous aerodynamist Ludwig Prandtl. From Prandtl he learned the close relationship between design and theory and "the method of abstracting the basic physical elements of a complex process … and analyzing it with simplified methods of mathematics." Von Kármán was also greatly influenced by David Hilbert, Göttingen's greatest mathematician, who taught him that nature was inherently mathematical. Von Kármán completed his doctorate thesis in 1908, and it was published the following year.

In March 1908 Von Kármán left for the Sorbonne, where he attended lectures of Madame Curie. That fall he accepted a position as a lecturer and assistant to Prandtl on a research project for Count Ferdinand von Zeppelin at the University of Göttingen. Here, in 1911 Von Kármán discovered that the oscillations of a cylinder in a flow tank were caused by the alternate shedding of vortices from the top and then the bottom of the cylinder. This phenomenon, called the Kármán vortex street, gives a scientific picture of the structure of the wake behind a moving body under certain conditions and enables the calculation of the drag of a sphere or cylinder. With this information engineers are able to minimize drag by streamlining. The Kármán vortex street also explains the oscillations of tall chimneys and radio towers as well as the collapse of the Tacoma Narrows Bridge in 1940.

In 1913 Von Kármán took the chair of aeronautics at the Aachen Technische Hochschule, where he set up a new program and constructed a wind tunnel which significantly advanced the knowledge of aerodynamics. When the war broke out in 1914, he was recalled by the army, and after a brief period he was transferred to the Luftarsenal, which marked the beginning of his association with military aviation. As director of the research laboratory, he pursued wind-tunnel experimentation, worked on machine gun-propeller synchronization, and pioneered an observational helicopter involving the use of counterrotating propellers. After the war Von Kármán spent a brief period as head of the Hungarian Department of Education. He returned to Aachen in 1919 to continue research and teaching. With the rise of Adolf Hitler, however, Von Kármán was convinced that he had to leave the increasingly oppressive environment of Nazi Germany. He moved to the United States, where he served as director of the Guggenheim Aeronautical Laboratory (1930-1949) and the Jet Propulsion Laboratory (1942-1945).

Air Force Consultant

The U.S. Navy, and then the Army, began sending students to Von Kármán's classes at the California Institute of Technology in 1932. By 1939 he was a close adviser to Gen. Henry Arnold, commander of the Army Air Corps, and with Von Kármán's urgings the corps embarked upon an aeronautical research program. Having convinced the Air Force that it was possible and necessary to fly faster than the speed of sound, Von Kármán was instrumental in the decision to build the famous Bell X-1 and later the X-15. Before the end of World War II Gen. Arnold requested Von Kármán to head the Science Advisory Board in Washington. As part of the effort to assess the technological progress created by the war, Von Kármán traveled to Germany to inspect laboratories and technical records and to talk with the country's scientists. Although he recognized the need to obtain the services of some German experts, he was opposed to the wholesale roundup of scientists as expressed in "Operation Paperclip," because he felt it would decimate European science and impede recovery. The outcome of these studies was the report "Where We Stand" (1945), which emphasized the technological character of World War II and the contribution of organized science.

Von Kármán felt that the enormous prestige of scientists could be used to bring about international peace; at the same time he maintained that the scientists as a group should act as adviser rather than advocate. It was his belief that "a scientist should be neither a [Edward] Teller nor an [Albert] Einstein insofar as public affairs are concerned." Near the end of his life he foresaw the creation of an international government and expressed great optimism in the role of science and technology in the future.