Dr Faustus of Modern Physics - Department of Speech, Music and ...
Dr Faustus of Modern Physics - Department of Speech, Music and ...
Dr Faustus of Modern Physics - Department of Speech, Music and ...
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1.4. BOHR: DIRECTOR OF MODERN PHYSICS 13<br />
1.4 Bohr: Director <strong>of</strong> <strong>Modern</strong> <strong>Physics</strong><br />
In 1921 the Theoretical Institute <strong>of</strong> <strong>Physics</strong> <strong>of</strong> Copenhagen University was<br />
created by the Danish physicist Niels Bohr, after a clever deal with Carlsberg<br />
brewery. Bohr had as a post doc <strong>of</strong> Ernst Rutherford in Manchester<br />
developed the first first quantized atomic model inspired by Planck, which<br />
gave him the 1922 Nobel Prize in <strong>Physics</strong>, at the same time as Einstein was<br />
awarded his 1921 Prize. Niels Bohr had taken on the duty to give Danish<br />
science back its past glory after Hans Christian Oersted (1777-1851), who<br />
discovered that electric currents create magnetic fields <strong>and</strong> thus opened to<br />
modern physics <strong>of</strong> electromagnetics. The pressure on Bohr to deliver was<br />
strong <strong>and</strong> the temptation to make a deal on the must have appeared irresistable...<br />
Bohr was a heavy pipe smoker.<br />
1.5 Pr<strong>and</strong>tl: Father <strong>of</strong> <strong>Modern</strong> Fluid Mechanics<br />
The German physicist Ludwig Pr<strong>and</strong>tl became the father <strong>of</strong> modern fluid<br />
mechanics by boldly facing the main open problem <strong>of</strong> classical continuum<br />
mechanics <strong>of</strong> turbulence in fluid flow as manifested in d’Alembert’s paradox<br />
formulated in 1755 but still unsolved at the start <strong>of</strong> the 20th century. Pr<strong>and</strong>tl<br />
extended the ambitions <strong>of</strong> Boltzmann <strong>and</strong> Planck <strong>of</strong> given the science <strong>of</strong> the<br />
German Empire a leading role, from basic physics to the main area <strong>of</strong> applied<br />
physics <strong>of</strong> fluid mechanics.<br />
D’Alembert had shown that the equations <strong>of</strong> fluid mechanics predicted<br />
zero drag in flows <strong>of</strong> vanishingly mall viscosity suggesting that it should<br />
be possible to move through air or water without resistance, at varaiance<br />
with all observation. To solve the paradox Pr<strong>and</strong>tl came up with the idea<br />
<strong>of</strong> a boundary layer as a thin zone connecting the free flow around a body<br />
moving through a fluid with the flow attaching to the boundary <strong>of</strong> the body.<br />
Pr<strong>and</strong>tl claimed that the observed drag resulted from vorticity generated in<br />
the boundary layer <strong>and</strong> changing the global flow pattern.<br />
This (eventually) brought Pr<strong>and</strong>tl world fame, but we shall see that his<br />
solution has devilish qualities, as it builds on a large effect from a vansihingly<br />
small cause which as working hypothesis is poison...
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