Theodore Theodorsen (January 8, 1897 – November 5, 1978) was a Norwegian-American theoretical aerodynamicist noted for his work at NACA (the forerunner of NASA) and for his contributions to the study of turbulence.
Early years Theodorsen was born at Sandefjord in Vestfold, Norway to parents Ole Christian Theodorsen, a chief engineer in the Norwegian merchant marine, and his wife Andrea Larsen. He was the oldest of six children. When Theodore’s father took the examinations for a merchant marine engineer's license, he was the only applicant who correctly answered a particularly difficult question. To his father’s surprise his then 12-year-old son was also able to solve the problem. At age 16, after finishing compulsory schooling, Theodorsen attended gymnasium in the nearby town of Larvik. Theodorsen's grades were so outstanding that he was admitted to the leading engineering university in Norway, the Norwegian Institute of Technology in Trondheim.
Emigration In 1922 Theodorsen graduated with a master's degree in mechanical engineering and was offered a position at the university as an instructor. That year one of his students was Lars Onsager, who became a lifelong friend and later went on to win a Nobel Prize in Chemistry. Theodorsen, like many Norwegian engineers, decided after some years as an instructor in Norway to emigrate. There were few jobs for engineers in Norway at the time. His wife's family knew a retired Norwegian sea captain who lived in Baltimore, so that became their American destination. They arrived in the United States on board the SS Stavangerfjord on August 25, 1924.
Johns Hopkins University Because there were few jobs in Baltimore, Theodorsen took a job working the third shift as an oiler at the Sparrows Point electrical generating plant 20 miles from Baltimore. Then Johns Hopkins University advertised for an instructor in mechanical engineering and he obtained the position. He taught at Johns Hopkins for five years. In 1928, Onsager, taught at Johns Hopkins for one semester. It was at that time that Onsager suggested to Theodorsen that he obtain a doctorate in physics. Theodorsen's thesis dealt with thermodynamic and aerodynamic themes that were to permeate much of his later work, which was developed in two parts: 1) shock waves and explosions and 2) combustion and detonation. Through the urging of Joseph Ames, president of Johns Hopkins University and Chairman of the Executive Committee of the National Advisory Committee for Aeronautics (NACA), Theodorsen went to NACA in 1929 as an associate physicist.
National Advisory Committee for Aeronautics The NACA facility adjoined Langley Air Force Base near Hampton, Virginia. The only in-house research arm of NACA at the time, it had a highly motivated young staff. The work atmosphere was informal though competitive, with much open stimulating discussion. However, conditions were rather primitive. The library consisted of one small shelf of books. Theodorsen used as his mainstays Hutte Mechanical Engineering Handbook and a set of the 1929 edition of the Handbuch der Physik. Within a short time Theodorsen was made head of the Physical Research Division, the other research divisions being Engine Research and Aerodynamics. Langley NACA was then in the process of expanding its experimental facilities to include a Full Scale Wind Tunnel and a Hydrodynamic Towing Basin for testing flying boat hulls. The proposed location of the towing basin had formerly been a bombing range. One of Theodorsen's first activities was the invention of an instrument for detecting buried metals and on its first use it located a live bomb. The ensuing years were highly productive ones for Theodorsen in a number of experimental and theoretical areas. Theodorsen improved thin airfoil theory by introducing the angle of best streamlining, developed the now classical and elegant theory of arbitrary wing sections, performed the first in-house noise research, worked on fire prevention in aircraft and on means of icing removal and prevention, contributed to the theory of open, closed and partially open wind-tunnel test sections, developed the basic theory of aircraft flutter and its verification, made early measurements of skin friction at transonic and supersonic speeds, developed the use of freon for experimental aeroelastic work, gave damping properties of structures and expanded general propeller theory. During World War II Theodorsen was called on for the analysis and troubleshooting of many aircraft problems and to help devise necessary modifications.
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