SOMMERFELD

GERMANY (see also List of Individuals)

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5.12.1868 Königsberg/RU - 26.4.1951 Munich/D

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Arnold Sommerfeld read mathematics and physics at Königsberg University, formerly in Prussia and today's Kaliningrad in Russia. After two years as an assistant at Göttingen University, he was appointed professor of mathematics at Clausthal University in 1897 and in 1900 professor of applied mathematics at Aachen University. From 1906 to 1931, he was a professor of theoretical physics at the University of Munich.

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Sommerfeld is famous for his contributions in mathematical physics, particularly for the extended atomic model. He also contributed to the lubrication theory and to fluid friction, however. The Orr-Sommerfeld equation describes an instability equation for viscous shear flow in a rectangular duct as the simplest arrangement, based on the researches of William McFadden Orr (1866-1934) and a paper published by Sommerfeld in 1904. The forth order ordinary differential equation may be solved subject to four boundary conditions. If the solution is plotted as a function of the Reynolds number R, arbitrary flows below a critical value remain stable, whereas flows may be either stable or unstable, depending on R and the wave number. Sommerfeld was an inspiring teacher and exerted a strong influence on the theoretical chemistry and physics. He was able to endure the political upheavals during the twenty years of retirement because of his dedication to science and preoccupation with scientific writing. Sommerfeld had also a particular gift for bringing together and furthering gifted pupils, thereby laying the foundations for the "Munich School" and the advancement of physics. After World War II he was mainly concerned with the publication of his lecture texts. He died as the result of a car accident.

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_{Anonymous (1969). Sommerfeld. A biographical dictionary of scientists: 483. Black: London. Buchwald, E. (1948). Sommerfelds 80. Geburtstag. Physikalische Blätter 4(11/12): 456-459. P Heisenberg, W. (1968). 100 Jahre Arnold Sommerfeld. Physikalische Blätter 24(12): 529-549. P}

_{Herrmann, A. (1975). Sommerfeld. Scienziati e tecnologi 3: 130-133. Mondadori: Milano. P}

_{Scherzer, O. (1938). Zu Arnold Sommerfelds 70. Geburtstag. Zeitschrift für den physikalischen und chemischen Unterricht 51(6): 217-222. P}

_{Sommerfeld, A. (1903). Physik. Teubner: Leipzig.}

_{Sommerfeld, A. (1927). Hydrodynamische Theorie der Schmiermittelreibung. Ostwalds Klassiker der exakten Wissenschaften 218. Akademische Verlagsgesellschaft: Leipzig.}

_{Sommerfeld, A. (1945). Mechanik der deformierbaren Medien. Becker&Erler: Leipzig. http://www-gap.dcs.st-and.ac.uk/ http://www-gap.dcs.st-and.ac.uk/∼history/Mathematicians/Sommerfeld.html}