A German physicist famous for his work in aeronautics, Prandtl was born at Freising, Bavaria, on February 4, 1875. He qualified at Munchen in 1900 with a thesis on elastic stability, and was professor of applied mechanics at Gottingen from 1904 until his death there on August 15, 1953. In 1925 he became director of the Kaiser Wilhelm Institute for Fluid Mechanics. His discovery (1904) of the "Boundary Layer" which adjoins the surface of a body moving in a fluid led to an understanding of skin friction drag and of the way in which streamlining reduces the drag of airplane wings and other moving bodies. His work on wing theory, published in 1918-1919, which followed that of F. W. Lanchester (1902-1907), but was carried out independently, elucidated the flow over airplane wings of finite span.
Prandtl made decisive advances in boundary layer and wing theories, and his work became the basic material of aeronautics. He also made important contributions to the theories of supersonic-flow and of turbulence, besides contributing much to the development of Wind Tunnels and other aerodynamic equipment. In addition, he devised the soap-film analogy for the torsion of noncircular sections and wrote on the theory of plasticity and of meteorology.