Walter Tollmien

Memorial plaque for Walter Tollmien and other scientists at the DLR entrance, Göttingen, Bunsenstrasse 10

Walter Tollmien (born October 13, 1900 in Berlin , † November 25, 1968 in Göttingen ) was a German flow physicist .

Life

Tollmien grew up in Wittenberg , where he passed his Abitur at the Melanchthon High School in October 1917. Since he was not drafted as a soldier for health reasons, he first had to do what is known as a patriotic service from October 1917 to April 1919 at the "Elbe" rubber works in Piestritz (near Wittenberg). He was only able to start studying in the summer semester of 1919 and initially studied mathematics and physics in Berlin, but then moved to Göttingen for the winter semester of 1920/21, where he worked with Felix Bernstein, Max Born , Richard Courant , James Franck , David Hilbert , Edmund, among others Landau , Carl Runge , Emil Wiechert , Adolf Windaus and, above all, heard from the then internationally known flow researcher Ludwig Prandtl , from whom he received his doctorate on May 7, 1924 with a thesis on "Development over time of the laminar boundary layers on the rotating cylinder".

Immediately after completing his doctorate, Ludwig Prandtl brought Tollmien to the Kaiser Wilhelm Institute for Flow Research in Göttingen, where he worked until November 1930. During this time one of his most important achievements falls, his famous investigation into the formation of turbulence by considering the stability of laminar boundary layer flows against small disturbances by means of the linear stability theory . Werner Heisenberg had already tried this problem in 1924 , but Walter Tollmien did not come to a conclusion until 1929. Thus, after decades of unsuccessful efforts, the solution of the complete perturbation problem within the framework of linearization by the “asymptotic stability theory” (i.e. for large Reynolds numbers) was successful. Tollmien's work, which was published in the news of the Göttingen Academy of Sciences in 1929 and later followed by numerous studies, gave this theory the form that is generally accepted today and has since been strictly proven.

In 1930 Theodore von Kármán brought Tollmien to the United States and from December 1930 to August 1933 Tollmien worked as a Research and Teaching Fellow at the Guggenheim Aeronautical Laboratory of the California Institute of Technology in Pasadena California, which was headed by Kármán .

Returned to Germany in the summer of 1933, his career made sluggish progress. Until the spring of 1934 he was unemployed, in April 1934 he got a job at the Kaiser Wilhelm Institute for Flow Research with a grant from the Notgemeinschaft der Deutschen Wissenschaft, where he was employed as a group leader in January 1935. In May 1935 he completed his habilitation at the University of Göttingen in applied mathematics and mechanics with the thesis: "A general criterion of the instability of laminar velocity distributions". There he taught as a private lecturer from the winter semester 1936/37. In November 1937 he was appointed to the chair for technical mechanics at the TH Dresden as the successor to the late Erich Trefftz , but was not appointed full professor until a year later, in accordance with the appointment practice at the time.

During this time he had also begun to delve deeper into the theory of compressible flows and carried out an investigation into the transition from subsonic to supersonic speeds. In addition, he was particularly interested in practical analysis, an indispensable tool for his treatment of hydrodynamic problems. This tendency was reflected in a much-noticed paper in which he emphasized the advantages of Adams' method for the approximate integration of ordinary differential equations. During his time in Dresden he also succeeded in accurately estimating the errors for the approximate solutions to his asymptotic stability theory and thus its strict justification. He reported on this in a memorable Dresden colloquium lecture in 1943. During the war, Tollmien u. a. “On the theory of wind tunnel turbulence” and was of course also involved in research that was important for the war effort, about which his contributions to the so-called Göttingen monographs from 1945/46 provide information. In these monographs, which consisted of several volumes, were only available as a typewritten script, the aerodynamicists who were brought together in Göttingen after the war had to report to the Allies about their research results from 1939 to 1945.

Due to the air raid on Dresden on 13./14. In February 1945 Tollmien had lost both his private apartment (and his extensive library) and his place of work due to the complete destruction of his institute and had already returned to Göttingen as a refugee at the beginning of March 1945. In September 1945 the British Resident Scientific Officer made him head of the “Outside Institutes” at the former aerodynamic research institute in Göttingen, which had been taken over by the British Ministry of Supply and Aircraft Production. In this function, Tollmien was primarily responsible as co-editor and editor for the "Göttingen Monographs".

Tollmien, who officially still held his Dresden ordinariate but did not want to go to the Soviet zone, then accepted the offer of a one-year stay in England, where he worked as a "German Scientist" in the Royals Aircraft Establishment Farnborough / Hants from June 1946 to August 1947 was active. In England, he was offered the chair of applied mechanics at the University of Göttingen as the successor to his teacher Ludwig Prandtl. He accepted this call and from September 1947 also acted as head of an independent department of the Kaiser Wilhelm Institute for Flow Research (from 1948 Max Planck Institute for Flow Research). After Albert Betz left , Tollmien became the sole director of the Max Planck Institute for Flow Research on May 1, 1957 .

Tollmien was

• since 1947 co-editor of the "Journal for Applied Mathematics and Mechanics",
• since 1952 permanent member of the organizing committee of the International Mechanics Congress,
• from 1953 to 1958 co-editor of the "Zeitschrift für Flugwissenschaften",
• since 1954 full member of the Göttingen Academy of Sciences .

In 1965 he received an honorary doctorate from the Bergakademie Clausthal Technische Hochschule.

In 1966 Tollmien retired, in October 1968 he gave up the management of the institute and on November 25, 1968 Walter Tollmien died in Göttingen.

On October 13, 2000, on his hundredth birthday, Walter Tollmien was honored with a plaque attached to the Institute for Flow Research in Göttingen.

Walter Tollmien married a second time after the death of his first wife in January 1947. From each marriage there were three children: two sons (one of whom died as an infant and the other died at the age of 35) and four daughters; one of them is the historian and writer Cordula Tollmien . Tollmien has four grandchildren and three great-grandchildren.

Act

Through his pioneering work as a researcher and his fruitful work as an academic teacher, Walter Tollmien made a decisive contribution to the development of fluid physics into an interdisciplinary science of the highest importance. It is thanks to him that modern hydrodynamics and aerodynamics were able to follow a mathematically rigorous path to investigate the still unsolved turbulence problem. It was his idea to introduce the concept of the stability of a flow as an essential characteristic of a flow. In this way he created the concept of perturbation calculus for the transition from the basic state of a flow to the turbulent state. With mathematical rigor, Walter Tollmien was able to prove that small disturbances in a given flow field can split up under certain conditions in order to convert the existing flow state into another ordered state. This process can continue like a cascade until a completely disordered state - turbulence - is reached. Walter Tollmien has shown a way in which a flow can develop from an orderly movement into a chaotic state. Modern turbulence research, which is the prototype for chaos theory , will therefore forever remain associated with the name Tollmien. The Tollmien-Schlichting waves that occur during the laminar-turbulent transition are named after him.

As an academic teacher, Walter Tollmien was held in high regard by his students. His lively and clear style of lecturing served as a role model for many of his students, who later went to teaching themselves. It is thanks to him that, after the Second World War, teaching at Göttingen University was enriched with many special lectures in applied mechanics, fluid dynamics and applied mathematics.

(From the application of Tollmien's student Karl G. Roesner for a memorial plaque for Tollmien of March 30, 2000)

Works (selection)

• Tollmien, Walter (1924): Temporal development of the laminar boundary layer on the rotating cylinder, Dissertation Göttingen 1924 .
• Tollmien, Walter (1929): About the origin of turbulence. 1st communication, in: Nachr. Ges. Wiss. Göttingen, Math. Phys. Class 1929, pp. 21-44 .
• Tollmien, Walter (1931): Grenzschichttheorie, in: Handbuch der Experimentalphysik IV, 1, Leipzig 1931, pp. 239–287.
• Tollmien, Walter (1935): A general criterion of the instability of laminar velocity distributions, in: Nachr. Ges. Wiss. Göttingen, Math. Phys. Class NF 1 1935, pp. 79-114 (habilitation thesis).
• Tollmien, Walter (1937): On the transition from subsonic to supersonic flows, in: ZAMM 17 (1937), pp. 117-136.
• Tollmien, Walter (1938): About the estimation of errors in the Adams method for integrating ordinary differential equations, in: ZAMM 18 (1938), pp. 83-90.
• Tollmien, Walter, together with Manfred Schäfer (1941): On the theory of wind tunnel turbulence, in: ZAMM 21 (1941), pp. 1–17.
• Tollmien, Walter (1945/46): Contributions to the Göttingen monographs: Stationary boundary layers. Basic principles and general results (B 1.1), instability of laminar boundary layers. Fundamentals and general results (B 3.1), passage through the speed of sound. Theory (C 6.1), Göttingen 1945/46 (machine script)
• Tollmien, Walter (1947): Asymptotic integration of the perturbation differential equation of plane laminar flows with high Reynolds numbers, in: ZAMM 25/27 (1947), pp. 33–50 and pp. 70–83.
• Tollmien Walter (1952): About vibrations in laminar flows and the theory of turbulence, in: Proc. 8th Int. Congr. Theor. and Appl. Mech., Istanbul 1952, pp. 23-47.
• Tollmien, Walter (1952/53): Decrease in wind tunnel turbulence according to Heisenberg's exchange approach as an initial value problem, in: Wissenschaftliche Zeitschrift der TH Dresden 2 (1952/53), pp. 443–448.
• Tollmien, Walter (1955): 50 years of boundary layer research, its development and problems, in: Henry Görtler / Walter Tollmien (eds.): 50 years of boundary layer research, Braunschweig 1955, pp. 1–12.
• Tollmien, Walter (1962): Aspects of Flow Physics (6th Ludwig Prandtl Memorial Lecture), in: ZFW 10 (1962), pp. 403-413.

literature

• Walter Tollmien: CV . In: Walter Tollmien: Temporal development of the laminar boundary layer on the rotating cylinder . Diss. Göttingen 1924.
• Manfred Schäfer: For guidance . In: Manfred Schäfer (Ed.): Miszellaneen der Angewandte Mechanik. Festschrift for Walter Tollmien on his 60th birthday. October 13, 1960 . Berlin 1962, pp. IX-XV.
• Karl G. Roesner: Application for honoring Walter Tollmien (memorial plaque). March 30, 2000 . City archive Göttingen, files memorial plaques.
• Werner Lauterborn : Laudation for the unveiling of the memorial plaque for Walter Tollmien, October 13, 2000 . In: Göttinger Jahrbuch . 48, 2000, p. 197 f.
• Personal estate of Walter Tollmien (outline of the career of Prof. Dr. W. Tollmien, excerpt from his personal file of the Max Planck Institute for Fluid Dynamics, directory of publications, directory of students, portrait and photos with Hahn and Heisenberg), private property of Cordula Tollmien

Web links

• Literature by and about Walter Tollmien in the catalog of the German National Library

Individual evidence

1. ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 241.
2. ↑ memorial plaque