Látogatók

Oldalainkat 499 vendég böngészi
Theodor von Kármán

 

 

Theodore von Kármán (original Hungarian name: Szőllőskislaki Kármán Tódor (May 11, 1881 – May 7, 1963) was a Hungarian-American engineer and physicist who was active primarily in the fields of aeronautics and astronautics. He is responsible for many key advances in aerodynamics, notably his work on supersonic and hypersonic airflow characterization.

 

Early life

 

Von Kármán was born into a Jewish family at Budapest, Austria-Hungary as Kármán Tódor. One of his ancestors was Rabbi Judah Loew ben Bezalel. He studied engineering at the city's Royal Joseph Technical University, known today as Budapest University of Technology and Economics. After graduating in 1902 he joined Ludwig Prandtl at the University of Göttingen, and received his doctorate in 1908. He taught at Göttingen for four years. In 1912 accepted a position as director of the Aeronautical Institute at RWTH Aachen, one of the country's leading universities. His time at RWTH Aachen was interrupted by service in the Austro-Hungarian Army 1915–1918, where he designed an early helicopter. He left RWTH Aachen in 1930.

 

Emigration and JPL

 

Apprehensive about developments in Europe, in 1930 he accepted the directorship of the Guggenheim Aeronautical Laboratory at the California Institute of Technology (GALCIT) and emigrated to the United States. In 1936, along with Frank Malina and Jack Parsons, he founded a company Aerojet to manufacture JATO rocket motors. He later became a naturalized citizen of the United States.

 

German activity during World War II increased U.S. military interest in rocket research. During the early part of 1943, the Experimental Engineering Division of the United States Army Air Forces Materiel Command forwarded to von Kármán reports from British intelligence sources describing German rockets capable of reaching more than 100 miles (160 km). In a letter dated 2 August 1943 von Kármán provided the Army with his analysis of and comments on the German program.

 

In 1944 he and others affiliated with GALCIT founded the Jet Propulsion Laboratory, which is now a Federally funded research and development center managed and operated by Caltech under a contract from NASA. In 1946 he became the first chairman of the Scientific Advisory Group which studied aeronautical technologies for the United States Army Air Forces. He also helped found AGARD, the NATO aerodynamics research oversight group (1951), the International Council of the Aeronautical Sciences (1956), the International Academy of Astronautics (1960), and the Von Karman Institute for Fluid Dynamics in Brussels (1956).

 

Last years

 

The "Kármán-Auditorium" at the RWTH Aachen University in Germany

 

In June 1944, von Kármán underwent surgery for intestinal cancer in New York City. The surgery caused two hernias, and von Kármán's recovery was slow. He returned to Pasadena around mid-September. Early in September, while still in New York, he met with U.S. Army Air Forces Commanding General Henry H. Arnold on a runway at LaGuardia Airport. Hap Arnold then proposed that von Kármán move to Washington, D.C. to lead the Scientific Advisory Group and become a long-range planning consultant to the military. Von Kármán was appointed to the position on 23 October 1944, and left Caltech in December 1944.

 

At age 81 von Kármán was the recipient of the first National Medal of Science, bestowed in a White House ceremony by President John F. Kennedy. He was recognized, "For his leadership in the science and engineering basic to aeronautics; for his effective teaching and related contributions in many fields of mechanics, for his distinguished counsel to the Armed Services, and for his promoting international cooperation in science and engineering."

 

While on a trip to Aachen in 1963, von Kármán died. He was buried in Pasadena, California. He never married.

 

Von Kármán's fame was in the use of mathematical tools to study fluid flow, and the interpretation of those results to guide practical designs. He was instrumental in recognizing the importance of the swept-back wings that are ubiquitous in modern jet aircraft.

 

Contributions

 

Sculpture inside the "Kármán Auditorium" at RWTH Aachen University

 

Specific contributions include theories of non-elastic buckling, unsteady wakes in circum-cylinder flow, stability of laminar flow, turbulence, airfoils in steady and unsteady flow, boundary layers, and supersonic aerodynamics. He made additional contributions in other fields, including elasticity, vibration, heat transfer, and crystallography. His name appears in at least the following concepts:

  • Föppl–von Kármán equations (large deflection of elastic plates)
  • Born-von Kármán lattice model (crystallography)
  • Chaplygin-Kármán-Tsien approximation (potential flow)
  • Falkowich-Kármán equation (transonic flow)
  • von Kármán constant (wall turbulence)
  • Kármán line (aerodynamics/astronautics)
  • Kármán-Howarth equation (turbulence)
  • Kármán-Nikuradse correlation (viscous flow; coauthored by Johann Nikuradse)
  • Kármán-Pohlhausen parameter (boundary layers)
  • Kármán-Treffz transformation (airfoil theory)
  • Prandtl-von Kármán law (velocity in open channel flow)
  • von Kármán integral equation (boundary layers)
  • von Kármán ogive (supersonic aerodynamics)
  • von Kármán vortex street (flow past cylinder)
  • von Kármán-Tsien compressibility correction.

 

Selected writings

  • Aerodynamics - Selected Topics in the Light of their Historical Development, Cornell University Press, Ithaca, 1954
  • Collected Works, (4 Volumes), Von Karman Institute, Rhode St. Genese, 1975 (limited edition book); also Butterworth Scientific Publ., London 1956. Many papers from volumes 1 and 2 are in German.
  • From Low Speed Aerodynamics to Astronautics, Pergamon Press, London, 1961
  • The Wind and Beyond - Theodore von Kármán Pioneer in Aviation and Pathfinder in Space, Little Brown, 1967 (with L. Edson)
  • Mathematical Methods in Engineering, McGraw Hill, 1940 (with M. A. Biot)

 

Honors and legacy

  • Each year since 1960 the American Society of Civil Engineers has awarded to an individual the Theodore von Karman Medal, "in recognition of distinguished achievement in engineering mechanics."
  • In 2005 von Kármán was named an Honorary Fellow of the Arnold Engineering Development Center (AEDC). Fellows of the AEDC are recognized as, "People who have made exceptionally distinguished contributions to the center's flight testing mission."
  • Craters on Mars and the Moon are named in his honor.
  • The boundary between the atmosphere and space is named the Kármán Line
  • In Irvine, CA there is a 5 mile street that runs through the heart of Irvine's business center named after him.
  • In 1977, RWTH Aachen University named its newly constructed lecture hall complex "Kármán-Auditorium" in memory of von Kármán's outstanding research contributions at the university's Aeronautical Institute.
  • University of Southern California Professor Shirley Thomas (after nearly two decades of petitioning) was able to create a postage stamp in his honor. It was first issued in 1992 with his image as an "Aerospace Scientist".
  • In 1956 von Kármán founded a research institute in Sint-Genesius-Rode, Belgium, which is now named after him: the von Karman Institute for Fluid Dynamics.
  • In 1948 von Kármán was awarded the Franklin Medal.
 
© 2008 BME GÉPÉSZMÉRNÖKI KAR | Template by Joomla Templates