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 nine. 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.

Further Reading

• A useful autobiography, written with the help of Lee Edson and published after von Kármán's death in 1963, is The Wind and Beyond: Theodore von Kármán, Pioneer in Aviation and Pathfinder in Space (1967), which also contains a list of his more than 100 books and papers.
• Gorn, Michael H., The universal man: Theodore von Kármán's life in aeronautics, Washington: Smithsonian Institution Press, 1992.