TAYLOR, GEOFFREY INGRAM

(b. London, England, 7 March 1886; d. Cambridge, England, 27 June 1975)

applied mechanics, physics.

Taylor’s father, Edward Ingram, was an artist. His mother, Margaret Boole, came from a family with a distinguished scientific background; she was the daughter of George Boole, the mathematician and logician, and her uncle was Sir George Everest, one of the founders of geodesy. Taylor studied from 1889 to 1905 at University College School and then went to Trinity College, Cambridge. He passed the natural science tripos in 1908 with first-class honors and was given a scholarship for research at Trinity, where he stayed for the rest of his life.

In 1925 Taylor married Stephanie Ravenhill, who shared his deep love for sailing; with their yacht Frolic they made several adventurous voyages, They had no children. Aside from these cruises and frequent travels abroad related to his scientific activity, Taylor had a very quiet life, spent in his house. Farmfield, at the periphery of Cambridge, and his room, next to Rutherford’s, at the Cavendish Laboratory. He was a rather shy man who disliked large scientific enterprises and preferred to concentrate on problems that could be formulated and managed by a single person, from the theoretical aspects to the design of the apparatus and the experimental observations.

Taylor received honorary degrees from about a dozen universities in Europe and America and was awarded honorary membership or fellowship in a number of scientific institutions. He was a member of the International Committee for the International Congresses of Applied Mechanics from their beginning in 1924.

Following a suggestion by J. J. Thompson in 1909, Taylor’s first research experiment was an investigation of interference fringes formed by light waves of very small intensity. After that he turned to topics in applied mechanics, and all of his following scientific production was in this field, though he used to label himself a classical physicist. In 1911 he was appointed to a temporary readership in dynamical meteorology established at Cambridge with funds given by Arthur Schuster, and the following year he spent six months aboard HMS Scotia, sent on a scientific expedition in the North Atlantic Taylor did experimental research on the mixing processes occurring in the lower layers of the atmosphere because of turbulent fluctuations of wind velocity, and on his return to Cambridge published a theoretical analysis of his data in which he put forward the idea of a “mixing length” characteristic of turbulent diffusion, allowing a rough analogy between turbulent motion of a fluid and the kinetic theory of gases.

This was Taylor’s first attack on a field in which, twenty years later, he would produce what is possibly his most important contribution to science. But his activity encompassed a much wider range of subjects in applied mechanics, both in theory and in experiment. During World War I, Taylor did research for the Royal Flying Corps at the Royal Aircraft Factory, Farnborough, where a team of scientists worked on aeronautical problems. With A. A. Grif-fith, he investigated the problem of the stress distribution in cylindrical shafts under torsion, which had a bearing on the manufacturing of stronger propeller shafts for aircraft, and starting from this he was led to think about the physical processes that limit the strength of solid materials. This analytical investigation was the source of a line of thinking that led him to his theory of dislocations in metal crystals, published in 1934.

In 1923 Taylor was appointed to a Royal Society research professorship, relieving him from teaching duties and allowing him to concentrate on research; as Rutherford said, he was “paid provided he does no work.” In the same year he published a study of the stability of steady flow between concentric circular cylinders in relative rotation. Here, as in most of his activity, he showed a peculiar ability to extract from the experimental study of a specific phenomenon general principles amenable to a thorough mathematical investigation. This ability was especially manifest in a beautiful paper on diffusion by continuous movements, published in 1921, in which the observation of pictures of the shape of the smoke plume from a chimney prompted him to introduce a correlation coefficient between velocity components at different times, regarded as random functions, to study the properties of turbulent diffusion.

In the following years an increasing familiarity with the phenomenology of turbulence, largely due to his association with the work done by B. M. Jones in wind tunnels at the Aeronautical Laboratory at Cambridge, and his interest in the mathematical work of Norbert Wiener on chaotic motion, converged to produce his famous papers on the statistical theory of turbulence (1935). In these works Taylor extended the idea first advanced in 1921 to a full description of the statistical properties of turbulence, introducing the concept of isotropic turbulence and showing that in this case the theoretical treatment on the basis of the correlation coefficient between the random fluctuating velocities led to results that could be tested, and were in fact confirmed, by data obtained in wind-tunnel experimental research. He crowned this line of research three years later, introducing the idea of the energy spectrum of turbulence with the use of Fourier’s transform analysis, a radically new approach in the field of fluid dynamics, dominated up to that time by semiempirical methods. Here again he made use of Wiener’s highly sophisticated mathematical work on harmonic analysis, translating it into a formulation that could be used for his specific problem and applied to obtain definite results.

During World War II Taylor was engaged in several fields as scientific consultant for war-related projects, mainly as an expert on blasts and shock waves. He was involved with the Manhattan Project, and he saw the first nuclear explosion in the desert at Alamogordo. He retired from the professorship in 1952, but kept doing research until 1972, when he suffered a severe stroke from which he never recovered.

BIBLIOGRAPHY

I. Original Works. His papers, published and unpublished, have been collected in G. I. Taylor. Scientific Papers, G. K. Batchelor, ed., 4 vols. (Cambridge, 1958–1971). His papers have been collected by G. K. Batchelor and deposited in the library of Trinity College. Cambridge. A catalog, compiled by Jeannine Alton, Harriot Weiskittel, and Julia Latham-Jackson, has been published by the Contemporary Scientific Archives Centre (Cambridge, 1979).

II. Secondary Literature. An authoritative biography by G. K. Batchelor appeared in Biographical Memoris of Fellows of the Royal Society, 22 (1976), 565–633, with a list of honors and a complete bibliography. More information about Taylor’s scientific activity is in G. K. Batchelor, “An Unfinished Dialogue with G. I. Taylor,” in Journal of Fluid Mechanics, 70 (1975), 625–638; and D. B. Spalding, “An Interview with Sir Geoffrey Taylor,” in Chartered Mechanical Engineer, 9 (1962), 186–191.

Giovanni Battimelli