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homepageIn the Interwar period, Henri Villat was in France the true leader
of researches on fluid mechanics, that is, at that time, of applied
mathematics and all mathematics relevant to applied mathematics. After
having organized the first post-WWI international congress of
mathematicians in 1920, Villat became the editor of the famous Journal
de mathématiques pure et appliqués and the director of
the influential book series Memorial des sciences mathématiques
and the Mémorial des sciences physique. From 1927 on, he held
the chair established by the Air Ministry at the Sorbonne in Paris and
was heading the important effort put in the study of the fluid
mechanics. However, while both his wake theory and his turbulence
theory had little outside success (except in the eyes of his students),
applied mathematics was despised by the loud generation of Bourbaki
mathematicians coming of age in the mid 1930s. How are we to understand
the contrasted assessment one can make of Villat's place in the history
of fluid mechanics?
In 1894 FW Lanchester read a paper before the Birmingham Natural
History and Philosophical Society in which he propounded, for the first
time, his now famous theory of flight. The paper was never published
and it was not until his two volume Aerial Flight (‘Aerodynamics’ 1907,
‘Aerodonetics’ 1908), modelled on ‘non-mathematical lines’, was
published that his ideas entered the wider public domain. However,
Lanchester’s work was difficult to follow and it was some time before
it was properly understood. Meanwhile, GH Bryan was laying the
foundations of the mathematical theory of aeroplane stability. His
pioneering paper ‘The longitudinal stability of aerial gliders’
appeared in 1904, and his classic Stability in Aviation, a mathematical
treatment of aircraft stability in all dimensions, in 1911.
L Bairstow, who was in charge of the National Physical Laboratory’s
Aerodynamics Division (founded 1909) until 1917, extended Bryan’s
theory, putting the mathematics into more convenient form (1914) and
making practical applications. Bairstow also made pioneering
investigations into wind tunnel design and authored numerous reports
for the Advisory Committee for Aeronautics (ACA). The first edition of
his book Applied Aerodynamics appeared in 1920. Another regular
contributor to ACA reports was H Glauert who had joined the Royal
Aircraft Factory, Farnborough, in 1916. Glauert, who was distinguished
for his mathematical ability, often provided the mathematical analysis
of the experimental work of his colleagues, covering on topics such as
propeller theory and the aerodynamics of a spinning aeroplane. Shortly
after the war Glauert was sent to Göttingen to learn about the
wind tunnels that had been developed there and it was this visit that
marked the beginning of the appreciation of Lanchester-Prandtl
aerodynamics in Britain. In this talk I shall discuss some of the work
of mentioned above, with particular emphasis on its significance for
the development of aviation theory in Britain during the First World
War and immediately afterwards.
The British effort to tackle the problems of aerodynamics was put on an official basis by the creation of the Advisory Committee for Aeronautics in 1909 under the presidency of the eminent physicist Lord Rayleigh. Although the Committee contained the engineer Frederick Lanchester, who pioneered the circulatory theory of lift, British experts were in general hostile to this theory until after the Great War. The reasons for opposing the theory were set out in a number of influential publications and I shall examine these in some detail (along with an unpublished source from G.I. Taylor). Significantly all of these reasons were well-known to German experts in aerodynamics (such as L. Prandtl) but they did not evoke a comparable hostility to the circulation theory. On the contrary German experts proceeded confidently down the path which was so unattractive to their British counterparts and developed the theory with great success. The situation is one in which the same evidence gave rise to very different conclusions within the two groups of experts. I shall propose a tentative explanation for this interesting, and potentially revealing, state of affairs.
The early contributions to wing theory by Lanchester, Kutta, Joukowski, and Prandtl all capitalized on important conceptual innovations of nineteenth-century hydrodynamics. The speaker will reflect on the nature of these innovations, on their meager success when taken separately, and on their fruitfulness when combined through targetted series of approximations.
The transition from laminar to turbulent flow has been—and still is—a much disputed research subject of fluid dynamics. I consider the history of transition studies about boundary layer flow along a flat plate (Blasius case) in the first half of the 20th century. The discovery of boundary layer oscillations (later called "Tollmien-Schlichting" or "TS-waves") in the USA during World War II vindicated a long disputed theory developed in Germany in the 1920s and 30s. In the 1950s, further experiments revealed more complexities (such as "turbulent spots"). Until today the onset of turbulence is regarded as one of the major unsolved riddles of science. The fundamental character of the problem, however, tends to obscure the practical interests which motivated its study throughout its long history.
The rise of 20th century aerodynamics happened under pressing circumstances. High hopes for a new military technology both allowed and urged researchers to accelerate their research activities. In particular, the need for reliable experimental systems - such as the wind tunnel - induced additional research activities whose object was the functioning of experimental systems themselves. The talk will discuss such research activities, proposing to analyse them as a kind of "meta-research" driven by the wish to stabilise the practice of ordinary research. The main example will be the gain in understanding of wind tunnel experimentation that arose from measuring the resistance of spheres in the years before World War I. I will argue that meta-research of this kind not only had the effect of improving experimental accuracy, but also of showing how different modes of scientific data production (such as experimental and mathematical data production) could successfully be integrated. Consequently, meta-research played a significant role in determining the paths of future scientific activities in aerodynamics.
Established in 1921, the Aeronautical Research Institute of Tokyo
Imperial University was a central aeronautical research institute
outside the military in prewar Japan. Furnishing several wind tunnels,
the Institute covered aerodynamic investigations, theoretical and
experimental. In this paper, I overview its aerodynamic investigations,
mainly following the works of the three leading researchers – Torahiko
Terada, Susumu Tomotika, and Itiro Tani. The physicist and essayist
Terada led the first phase of aerodynamic researches at the institute.
The physics graduate Tomotika conducted theoretical researches, based
on Prandtl’s and others’ aerodynamic and hydrodynamic theories. His
researches were, however, especially influenced from G.I. Taylor during
his visit to Cambridge and other European institutes in the mid 1930s.
The aeronautics graduate Tani followed up Tomotika’s researches on
boundary layer, focused on the transition from laminar to turbulent
flow, and proposed an engineering theory to design laminar flow
airfoil.
Prandtl’s decisive move was to introduce a model that provided a
physical/causal conception of viscous flow at high Reynolds numbers.
It facilitated an approximate solution to the Navier-Stokes equations,
which in turn gave rise to many special applications. After a detailed
account of Prandtl’s achievement, the article discusses the role of the
physical model and its experimental and mathematical significance. It
is shown that the mathematical simplification furnished by the physical
model greatly expanded the explanatory capacity of the theory which the
Navier-Stokes equations alone could not provide. This contradicts
Morrison’s and Morgan’s recently proposed philosophical discussion of
models.
Talking about „stream-line“ refers to a design movement of the
1920s. However, the application of exact scientific methods to the
construction of technical artifacts means something else. Up to the
1930s, German automotive research and car manufacturing lagged behind
compared to international standards. On the other hand, Gemany had
introduced aerodynamics to aircraft and airship design successfully,
already from World War I on. The paper lines out the appropriation of
the wind-tunnel by automotive engineering under the special conditions
of the German innovation system before and after 1945.
The 'quantification' of waterwheels and the development of hydrodynamics are two separated processes which evolved parallel during the 18th century. Although we find outstanding scientists involved in both realms the theoretical framework of calculating the design of waterwheels and water turbines differs considerable from that of fluid mechanics. The talk will deal with theoretical attemps to calculate the operation of waterwheels in the first half of the 19th century. By means of three German monographs I will discuss terms and concepts of this theories and their relation to hydrodynamic theories. The three monographs are: Franz von Gerstner: Abhandlung über die oberschlächtigen Wasserräder, Prag: Gottlieb Haase, 1809; Moritz Rühlmann: Die horizontalen Wasserräder und besonders die Turbinen und Kreiselräder, ihre Geschichte, Construction und Theorie, Chemnitz: Expedition des Gewerbeblattes für Sachsen, 1840; Ferdinand Redtenbacher: Theorie und Bau der Wasser-Räder, Mannheim: Friedrich Bassermann, 2. Aufl. 1858 (1. Aufl. 1846).
Even though ballistics and aerodynamics developed in the 20th century in an interplay, history of science has not yet studied this subject in detail. The talk will present some preliminary results of a case study about the ermergence of a new 'experimental system' (Rheinberger) for ballistic research: the supersonic wind tunnel projected by Ludwig Prandtl at the end of World War One. Based on his expertise in gas dynamics Prandtl submitted a memorandum to the War Ministry in 1918, in which the essentials of the construction of a supersonic wind tunnel were developed. The project was postponed due to the collapse of German Empire. But since the early 1920s high-velocity experiments were taken up again. They lead to the construction of a supersonic wind tunnel at the KWI für Strömungsforschung in 1928, used for research on projectiles and profiles. After 1933, when the German Air Ministry under Göring provided substantial funds, this wind tunnel was taken over by the expanding Aerodynamische Versuchsanstalt (AVA), as the experimental nucleus of a working group on high-velocity research. In 1937 this group under the direction of Otto Walchner was transformed into one of the eight sub-institutes of the AVA. Several supersonic wind tunnels were build until 1945 in which secret ballistic research was done for the military and for private companies. What were the crucial problems of this research and what kind of difficulties did the scientists face in the development of this new experimental system?
Richard von Mises (1883-1953) contributed on several practical and theoretical levels to hydro- and aerodynamics. He emphasized the mathematical nature of the problems discussed, suggested early (1908) the statistical character of several of them, and gave detailed additions to the 5th edition of H. Lamb's Hydrodynamics, when the book appeared in German translation in 1931.In some more detail, von Mises' remarkable discovery of the "aerodynamic center" of a two-dimensional wing (1917-20) and his function-theoretic treatment (in cooperation with mathematicians such as L. Bieberbach) of a rather general group of profiles will be discussed, which was later on named the "Mises family". Reasons for the apparently rather limited applicability of his wing theory seem to lie in a misguided aspiration, on von Mises' part, for mathematical generality, in a certain decline of function-theoretic and geometrical methods and in the interplay between theory and experimental facilities such as wind-tunnels (not at von Mises' disposal) in an age of beginning mass-production of airplanes.
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