Jakob Ackeret and the "Institut für Aerodynamik (IfA)''

Prof. Ackeret

The Institute of Fluid Dynamics was founded in 1932 as "Institut für Aerodynamik (IfA)'' by Professor Jakob Ackeret (1898-1981), who remained its director until his retirement in 1967.

Ackeret was one of the pioneers of modern aerodynamics. He was not only the key figure in the history of the Institute for a period of more than 35 years, but also one of the most influential personalities in the Swiss science and engineering community of his time.

Ackeret received his Diploma degree in Mechanical Engineering from ETH in 1920 under the supervision of A. Stodola. From 1921 to 1927 he worked with Ludwig Prandtl at the "Aerodynamische Versuchsanstalt'' in Göttingen, witnessing (and being part of) a legendary period in the development of modern fluid dynamics. In 1925 he published his laws for the lift and drag of sharp slender profiles in supersonic flow, which became famous as Ackeret's formulae. His influential article on gas dynamics, summarizing this new important area of fluid mechanics, appeared in 1927 in the "Handbuch der Physik''. It was Ackeret who, in this article, introduced the now common term "Mach number'' for the ratio of flow velocity to the speed of sound. Another article on cavitation was accepted as his doctoral thesis at ETH.

Before joining ETH as Professor of Aerodynamics in 1931, Ackeret worked at Escher Wyss AG in Zurich as Chief Engineer of Hydraulics, where he applied, with great success, modern aerodynamics to the design of turbines.

At ETH, Ackeret founded the IfA where he soon built two large wind tunnels. The subsonic tunnel, equipped with a 2m x 3m test section, has remained in use up to the present day for research, teaching, and industrial projects. The second tunnel for supersonic flow was based on Ackeret's original designs and became world-famous as the first supersonic tunnel with a closed circuit. Based on these, then state-of-the-art facilities, a period of more than three decades of pioneering work in aerodynamics evolved, which made "Zürcher Aerodynamik" an academic trade name.

Ackeret and his coworkers were active in a broad range of fundamental and applied research topics. Many of these projects are documented in the 32 volumes of the "Mitteilungen aus dem Institut für Aerodynamik''. Topics include:

Throughout his time at ETH, Ackeret actively participated in the solution of practical engineering problems, e.g. the design of variable pitch propellers for ships and airplanes. His most important invention (together with C. Keller) was the gas turbine with a closed circuit.

In addition to his professional work in aerodynamics, Ackeret maintained a lifelong interest in the history of science and technology. Still more fascinating for his colleagues and coworkers was his deep understanding of modern physics and his clear vision of future developments in science and engineering.


Festschrift Jakob Ackeret.
Zum 60. Geburtstag am 17. März 1958. ZAMP Vol. IXb, 1958. Birkhäuser Verlag, Basel.

F. Schultz-Grunow,
50 Jahre Institut für Aerodynamik an der ETH Zürich - J. Ackeret: Persönliche Erinnerungen. Schweizer Ingenieur und Architekt 21, 1983, pp. 1-8.

N. Rott,
Jakob Ackeret and the history of the Mach number. Annual Review of Fluid Mechanics, 17, 1985, pp. 1-9.

Georges Bridel,
Jakob Ackeret. In Schweizer Pioniere der Wirtschaft und Technik 67, Verein für wirtschaftshistorische Studien, Meilen, 1998, 73-92.

Rudolf Mumenthaler, Roland Jung,
Jakob Ackeret (1898-1981), Pionier der Aerodynamik. Virtuelle Ausstellung der ETH-Bibliothek, 1998 / 2001


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