Pipe flow has been a challenge that gave rise to investigations on turbulence—long before turbulence was discerned as a research problem in its own right. The discharge of water from elevated reservoirs through long conduits such as for the fountains at Versailles suggested investigations about the resistance in relation to the different diameters and lengths of the pipes as well as the speed of flow. Despite numerous measurements of hydraulic engineers, the data could not be reproduced by a commonly accepted (...) formula, not to mention a theoretical derivation. The resistance of air flow in long pipes for the supply of blast furnaces or mine air appeared even more inaccessible to rational elaboration. In the nineteenth century, it became gradually clear that there were two modes of pipe flow, laminar and turbulent. While the former could be accommodated under the roof of hydrodynamic theory, the latter proved elusive. When the wealth of turbulent pipe flow data in smooth tubes was displayed as a function of the Reynolds number, the empirically observed friction factor served as a guide for the search of a fundamental law about turbulent skin friction. By 1930, a logarithmic “wall law” seemed to resolve this quest. Yet pipe flow has not been exhausted as a research subject. It still ranks high on the agenda of turbulence research—both the transition from laminar to turbulent flow and fully developed turbulence at very large Reynolds numbers. (shrink)

ArgumentDuring the interwar period research on turbulence met with interest from different areas: in aeronautical engineering turbulence became a subject of experimental study in wind tunnels; in naval architecture and hydraulic engineering turbulence research was on the agenda because of its role for skin friction; applied mathematicians and theoretical physicists struggled with the problem to determine the onset of turbulence from the fundamental hydrodynamic equations; experimental physicists developed techniques to measure the velocity fluctuations of turbulent flows. In this paper I (...) describe the rise of turbulence in the 1920s and 1930s as a research field under the label of applied mechanics. Although the focus is on Germany, the international development of this research field is illuminated by the role which Ludwig Prandtl played as its acknowledged “chief” (G. I. Taylor). I argue that the multifaceted character of this research field calls for an epistemology and historiography which intrinsically takes the interaction of science and engineering into account. (shrink)

The efflux problem deals with the outflow of water through an orifice in a vessel, the flow over the crest of a weir and some other ways of discharge. The difficulties to account for such fluid motions in terms of a mathematical theory made it a notorious problem throughout the history of hydraulics and hydrodynamics. The treatment of the efflux problem, therefore, reflects the diverging routes along which hydraulics became an engineering science and hydrodynamics a theoretical science out of touch (...) with applications. By the twentieth century, the presentation of the efflux problem in textbooks on hydraulics had almost nothing in common with that in textbooks on hydrodynamics. (shrink)

Nikolaus von Kues, eine Schwellengestalt zwischen Mittelalter und Neuzeit, gewinnt in einer Zeit, die sich selbst als Ubergangsepoche wahrnimmt, wieder starkere Aufmerksamkeit. Er steht in dem noch ungewissen Morgenlicht einer Epoche, deren Abenddammerung gegenwartig vielfach diagnostiziert wird. Wichtige Themen, an denen Stellung und Bedeutung des Cusanus immer wieder aufbrechen, sind der Individualitatsbegriff, der cusanische Beitrag zur Ausbildung der modernen Naturwissenschaften, die Kreativitat des Denkens, die Reichweite seiner konjekturalen Erkenntnislehre und die gesellschaftliche Rolle der Toleranz im Dialog der Kulturen. Die kulturwissenschaftliche (...) Neuorientierung der Geisteswissenschaften schuf auch in der Cusanusforschung Raum fur neue Forschungsfelder wie das Verhaltnis von Malerei und Philosophie. Die sich seit Jahrzehnten anbahnende Neubewertung der cusanischen Philosophie wird im vorliegenden Band umfassend dokumentiert und weitergefuhrt. Alle Beitrage eint die Uberzeugung, dass die Hinterlassenschaften des Theologen, Philosophen, Naturwissenschaftlers, Mystikers, Juristen und Politikers Nicolaus Cusanus fur ein an der Praxis des menschlichen Lebens orientiertes gegenwartiges Philosophieren fruchtbar gemacht werden kann. Der vorliegende Band dokumentiert Ergebnisse von sechs selbstandigen, aber koordinierten Tagungen der internationalen Cusanusforschung aus dem Jubilaumsjahr 2014. (shrink)

Das Schleiermacher-Archiv ist primär ein begleitendes Publikationsorgan für die seit 1980 erscheinende Gesamtausgabe der Werke Friedrich Schleiermachers (KGA), welches Materialien und Untersuchungen veröffentlicht, die in engerer Beziehung zur KGA stehen. In Sammelbänden werden zudem Beiträge dokumentiert, die auf internationalen Schleiermacher-Kongressen vorgetragen worden oder in diesem Zusammenhang entstanden sind.

This is a comprehensive biography of Ludwig Prandtl (1875-1953), the father of modern aerodynamics. His name is associated most famously with the boundary layer concept, but also with several other topics in 20th century fluid mechanics, particularly turbulence (Prandtl's mixing length). Among his disciples are pioneers of modern fluid mechanics such as Heinrich Blasius, Theodore von Kármán and Walter Tollmien. Furthermore, Prandtl founded the Aerodynamische Versuchsanstalt (AVA) and the Kaiser-Wilhelm-Institut für Strömungsforschung in Göttingen, both of them seeds for the growth (...) of fluid mechanics in Germany. Yet Prandtl was also a representative of aeronautical research - from Imperial Germany via the Weimar Republic to the "Third Reich". Although not a party member, he assumed the role of a goodwill ambassador for Nazi Germany. This objective treatment of his career will be of interest to all scientists and historians wanting to learn more about Prandtl's influence and the early development of fluid- and aerodynamics. (shrink)

Since its discovery in 1912, X-ray crystallography has become a most useful tool in physics, chemistry, material science, mineralogy, metallurgy, and even in the biological sciences. In 1914, Max von Laue was awarded the Nobel Prize “for the discovery of X-ray diffraction by crystals,” followed by the 1915 Nobel Prize to William Henry Bragg and William Lawrence Bragg “for their services in analysis of crystal structure by means of X-rays.” And these early Nobel prizes marked only the beginning of X-ray (...) crystallography as one of the most fruitful methods in the history of modern science. A 100 years after Laue’s Nobel Prize and 50 years after another Nobel Prize to Dorothy Hodgkin “for her determination by X-ray technique of the structures of important biochemical substances,” the UN proclaimed 2014 the International Year of Crystallography. “In all, 45 scientists have been awarded over the past century for work that is either directly or indirectly related to crystallo .. (shrink)