Philip Geoffrey Saffman FRS (19 March 1931 – 17 August 2008) was a mathematician and the

Theodore von Kármán Theodore von Kármán ( hu, ( szőllőskislaki) Kármán Tódor ; born Tivadar Mihály Kármán; 11 May 18816 May 1963) was a Hungarian-American mathematician, aerospace engineer, and physicist who was active primarily in the fields of aeronaut ...

Professor of

Applied Mathematics Applied mathematics is the application of mathematical methods by different fields such as physics, engineering, medicine, biology, finance, business, computer science, and industry. Thus, applied mathematics is a combination of mathematical s ...

and

Aeronautics Aeronautics is the science or art involved with the study, design, and manufacturing of air flight–capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies ...

at the

California Institute of Technology The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...

Education and early life

Saffman was born to a

Jewish Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...

family in

Leeds Leeds () is a city and the administrative centre of the City of Leeds district in West Yorkshire, England. It is built around the River Aire and is in the eastern foothills of the Pennines. It is also the third-largest settlement (by populati ...

, England, and educated at Roundhay Grammar School and

Trinity College, Cambridge Trinity College is a constituent college of the University of Cambridge. Founded in 1546 by Henry VIII, King Henry VIII, Trinity is one of the largest Cambridge colleges, with the largest financial endowment of any college at either Cambridge ...

which he entered aged 15. He received his Bachelor of Arts degree in 1953, studied for Part III of the

Cambridge Mathematical Tripos The Mathematical Tripos is the mathematics course that is taught in the Faculty of Mathematics at the University of Cambridge. It is the oldest Tripos examined at the University. Origin In its classical nineteenth-century form, the tripos was ...

in 1954 and was awarded his PhD in 1956 for research supervised by

George Batchelor George Keith Batchelor FRS (8 March 1920 – 30 March 2000) was an Australian applied mathematician and fluid dynamicist. He was for many years a Professor of Applied Mathematics in the University of Cambridge, and was founding head of the ...

Career and research

Saffman started his academic career as a lecturer at the University of Cambridge, then joined

King's College London King's College London (informally King's or KCL) is a public research university located in London, England. King's was established by royal charter in 1829 under the patronage of King George IV and the Duke of Wellington. In 1836, King's ...

as a

Reader A reader is a person who reads. It may also refer to: Computing and technology * Adobe Reader (now Adobe Acrobat), a PDF reader * Bible Reader for Palm, a discontinued PDA application * A card reader, for extracting data from various forms of ...

. Saffman joined the Caltech faculty in 1964 and was named the Theodore von Kármán Professor in 1995. According to Dan Meiron, Saffman "really was one of the leading figures in fluid mechanics," and he influenced almost every subfield of that discipline. He is known (with his co-author

Geoffrey Ingram Taylor Sir Geoffrey Ingram Taylor OM FRS FRSE (7 March 1886 – 27 June 1975) was a British physicist and mathematician, and a major figure in fluid dynamics and wave theory. His biographer and one-time student, George Batchelor, described him as ...

) for the Saffman–Taylor instability in

viscous fingering The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

of fluid boundaries, a phenomenon important for its applications in

enhanced oil recovery Enhanced oil recovery (abbreviated EOR), also called tertiary recovery, is the extraction of crude oil from an oil field that cannot be extracted otherwise. EOR can extract 30% to 60% or more of a reservoir's oil, compared to 20% to 40% using ...

, and for the Saffman–Delbrück model of

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...

in membranes which he published with his Caltech colleague and Pasadena neighbour

Max Delbrück Max Ludwig Henning Delbrück (; September 4, 1906 – March 9, 1981) was a German–American biophysicist who participated in launching the molecular biology research program in the late 1930s. He stimulated physical science, physical scientist ...

. He made important contributions to the theory of

vorticity In continuum mechanics, vorticity is a pseudovector field that describes the local spinning motion of a continuum near some point (the tendency of something to rotate), as would be seen by an observer located at that point and traveling along wi ...

arising from the motion of ships and aircraft through water and air; his work on

wake turbulence Wake turbulence is a disturbance in the atmosphere that forms behind an aircraft as it passes through the air. It includes variety of elements, the most significant of which are wingtip vortices and jetwash. Jetwash refers to the rapidly moving g ...

led the airlines to increase the minimum time between takeoffs of aircraft on the same runway. Saffman also studied the flow of

spheroid A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has cir ...

al particles in a fluid, such as bubbles in a carbonated beverage or corpuscles in blood; his work overturned previous assumptions that inertia was an important factor in these particles' motion and showed instead that

Non-Newtonian A non-Newtonian fluid is a fluid that does not follow Newton's law of viscosity, i.e., constant viscosity independent of stress. In non-Newtonian fluids, viscosity can change when under force to either more liquid or more solid. Ketchup, for exa ...

properties of fluids play a significant role. Along with his many research papers, Saffman wrote a book, ''Vortex Dynamics'', surveying a field to which he had been a principal contributor. Russel E. Caflisch writes that "This book should be read by everyone interested in vortex dynamics or fluid dynamics in general."

Awards and honours

Saffman was elected a

Fellow A fellow is a concept whose exact meaning depends on context. In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements. Within the context of higher education ...

of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...

and a

Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...

in 1986, and the recipient of the

American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of k ...

Otto Laporte Award The Otto Laporte Award (1972–2003) was an annual award by the American Physical Society (APS) to "recognize outstanding contributions to fluid dynamics" and to honour Otto Laporte (1902–1971). It was established as the Otto Laporte Memorial ...

..Laporte Award recipients
. Retrieved 22 August 2008. His nomination for the Royal Society reads:

Personal life

Saffman was survived by his wife (Ruth Arion whom he married in 1954), three children (Mark, Louise, Emma), and eight grandchildren (Timothy, Gregory, Rae, Jenny, Nadine, Aaron, Miriam, Alexandra and Andrey.

References

* P.A. Davidson, Y. Kaneda, K. Moffatt, and

K.R. Sreenivasan Katepalli Raju Sreenivasan is an aerospace scientist, fluid dynamics, and applied physicist whose research includes physics and applied mathematics. He studies turbulence, nonlinear and statistical physics, astrophysical fluid mechanics, and cr ...

(eds, 2011). ''A Voyage Through Turbulence'', chapter 12, pp 393–425,

Cambridge University Press Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press A university press is an academic publishing hou ...

{{DEFAULTSORT:Saffman, Philip Geoffrey 1931 births 2008 deaths Alumni of Trinity College, Cambridge 20th-century British mathematicians 21st-century British mathematicians Fluid dynamicists California Institute of Technology faculty Fellows of the American Academy of Arts and Sciences Fellows of the Royal Society Academics of King's College London