KRIES

GERMANY (see also List of Individuals)

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6.10.1853 Roggenhausen/PL - 30.12.1928 Freiburg/D

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Johannes von Kries graduated from the University of Leipzig in 1875. He was from 1876 to 1877 an associate of Hermann von Helmholtz (1821-1894) at Berlin University. After Lecturership at Leipzig, he was appointed in 1880 associate professor of physiology in Freiburg im Breisgau, and there promoted to full professor in 1882. von Kries retired in 1924 after having founded Zeitschrift für Psychologie, and after having been awarded the Prussian Order Pour le Mérite in 1918 along with three Honorary Doctorates.

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Waterhammer is a phenomenon associated with unsteady conduit flow. The first physical description was given by the Italian Luigi Federico Ménabréa (1809-1896) who presented an expression for surge propagation in 1858 containing both the effects of fluid density and conduit wall elasticity. The Swiss Jules Michaud (1848-1920) expanded the approach for application in hydropower installations in 1878. In parallel, the Russian Nikolai Egorovich Zhukovsky (1847-1921) published his first paper in 1878 in which pressure differences in pressurized fluid flows are related to variations in velocity. A complete theory of unsteady pipe flow along with a solution for frictionless flow was finally introduced by the Italian Lorenzo Allievi (1856-1940) in 1902. Both Zhukovsky and von Kries were famous in other fields of technology, whereas the other authors are exclusively known for their particular contributions in waterhammer theory. von Kries' 1883 paper described manometer measurement on blood pressure. In later papers he realized the laminar flow in human arteries of which the maximum velocity is equal twice the average, a relation verified with detailed observations.

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_{Kries, J. von (1883). Über die Beziehungen zwischen Druck und Geschwindigkeit, welche bei der Wellenbewegung in elastischen Schläuchen entstehen. Festschrift 50. Versammlung Deutscher Naturforscher und Ärzte, Naturforschende Gesellschaft: Freiburg/B.}

_{Lorenz-Mussler, S. (1996). Brücken zwischen Naturwissenschaft, Klinik und Geisteswissenschaft - Johannes von Kries in Freiburg. Inaugural-Dissertation. Institut für Geschichte der Medizin. Albert-Ludwigs-Universität: Freiburg/B.}

_{Oser, B.M. (1983). Leben und Werk des Physiologen Johannes von Kries - Sinnesphysiologie und Erkenntniskritik. Inaugural-Dissertation. Institut für Geschichte der Medizin. Albert-Ludwigs-Universität: Freiburg/B.}

_{Tijsseling, A.S., Anderson, A. (2004). A precursor in waterhammer analysis - Rediscovering Johannes von Kries. 9th Intl. Conf. Pressure Surges: 739-751. BHR: London. P}