- SAMUEL NEWBY CURLE

B.Sc., M.Sc., Ph.D. (Manchester)Newby Curle, Gregory Professor of Applied Mathematics at the University of St Andrews, died suddenly on 27th June 1989, while walking in the Yorkshire moors near Settle with his wife Shirley.

Newby Curle was born in Sunderland on 18th June 1930, son of Samuel Curle and Edith Newby Curle, formerly Holmes. He obtained his early schooling at Barnes School, Sunderland, before attending the Bede Grammar School. There his mathematics master was E M Maccoby, a strict Orthodox Jew who had rejected a University career at a time when lectures were frequently given on Saturday mornings. Maccoby's pupils included Sydney Goldstein, J W Craggs and Curle, all three of whom became professors in mathematics.

In 1948, Curle was awarded a state scholarship to become an undergraduate at Manchester University in the distinguished mathematics department then led by Goldstein. His teachers there included many who later attained eminence, including M J (now Sir James) Lighthill, D S Jones, G Higman, D Rees, J W S Cassels, G E H Reuter and (in Physics) A C B (later Sir Bernard) Lovell. Newby Curle was joint winner of the Dalton Mathematical Scholarship in 1949 and outright winner in 1950. After graduating with first class honours in 1951, Curle remained in Manchester to work for the degrees of M.Sc. (awarded 1952) and Ph.D. (awarded 1955). His Ph.D. studies were guided by Lighthill, who had recently developed his influential theory of aerodynamic sound. Curle's Ph.D. thesis concerned the edge-tones generated when an air jet strikes a sharp edge and the influence of solid objects as dipoles in the production of aerodynamic sound.

After a brief spell as an Assistant Lecturer in Manchester, Curle joined the Aerodynamics Division of the National Physical Laboratory in 1954. There he was rapidly promoted to Senior Scientific Officer in 1955 and then, in 1961, to Principal Scientific Officer and leader of the boundary-layer research group. For part of that time he served on the Noise Research Committee of the Aeronautical Research Council. In 1961, Southampton University appointed him to the Hawker-Siddeley Readership in the Department of Aeronautics. There, he continued as an independent member of the Noise Research Committee, acted as a consultant to the Boeing International Corporation and, in 1963, was awarded the Orville Wright Prize by the Royal Aeronautical Society for the best research paper published in the 'Aeronautical Quarterly' during the previous year. In 1964, he transferred to the Department of Mathematics at Southampton, but within a few years both he and his colleague B (now Sir Bryan) Thwaites had left.

Curle's contributions during this exciting period for fluid-dynamical research encompassed many topics: unsteady free-boundary flows, aerodynamic noise generation, hydrodynamic stability of jets and wakes and, perhaps most importantly, compressible and incompressible boundary-layer theory. The latter work formed the basis for a 1961 research monograph, 'The Laminar Boundary Layer Equations', published by Oxford University Press. At this time, Curle was a leading exponent of the approximate methods then necessary to calculate the behaviour of the flow past aerofoils; for example, to predict the occurrence and location of boundary-layer separation that can lead to disastrous stall of aircraft. His time at N.P.L. had sharpened his facility for rapid arithmetic calculations and had equipped him with an armoury of techniques, the validity of which was not always apparent to others, but which almost unerringly led him to a close estimate of the right answer.

In 1967, Newby Curle was appointed to the Gregory Chair of Applied Mathematics at St Andrews University, in succession to its first holder, D E Rutherford. There he devoted himself to teaching, course development, administration and, in the happy days of university expansion, to building by judicious appointments a strong and active Applied Mathematics Department. Long before the advent of university schools liaison services, he took a personal initiative in visiting local schools to foster the study of applied mathematics. He served on the University Court for a time, and on numerous committees. During 1982-85, he was Dean of the Faculty of Science and earned much respect for his fairness and sound sense in guiding the faculty through a financially-difficult period. He was elected a Fellow of the Royal Society of Edinburgh in 1977.

His lecturing style, like his conversation, was genial, informal and anecdotal (on arriving in St Andrews, he immediately broke the tradition of wearing a gown to lecture). He was more interested in practical problems, and the procedures that give answers to them, than in more esoteric general theories: a viewpoint that sometimes exasperated his pure mathematical colleagues! But all former colleagues and hundreds of students have reason to remember with gratitude his advice, encouragement and patient attention to detail.

The two volumes of his deservedly successful undergraduate textbook 'Modern Fluid Dynamics', written with Southampton colleague H J Davies, appeared in 1968 and in 1971. As series editor for the publishers Van Nostrand, Curle encouraged and advised many authors of undergraduate mathematics texts: his own 'Applied Differential Equations' of 1972 is characteristically clear and down-to-earth (a Portuguese translation appeared in 1975). He also contributed articles to an Encyclopedic Dictionary of Physics and to various other scientific compendia.

His later research interests focussed on practical methods for using series expansions to solve various thorny problems that arise in boundary-layer theory. Accelerated convergence techniques allied to computer calculations (always performed by willing helpers, not himself!) shed light on the effective range of validity of such methods and on the location of singularities of the governing equations. He maintained an active research correspondence, spanning many years, with others concerned with power-series approximations in boundary-layer flows. His correspondence with the late K Stewartson and with M Van Dyke appears to have been particularly fruitful for all three participants, whose different methods of analysis sometimes provided mutual corroboration and sometimes identified errors or defects.

Curle's thirty published research papers appeared in Proc. R. S. Lond. (A), Proc. R. S. Edin. (A), Aero. Quart., Jour. I.M.A., Quart. J. Mech. Appl. Math., J. Fluid Mech., Phys. Fluids and as A.R.C. documents.

A committed Methodist by upbringing, Newby Curle had an optimistic, cheerful, common-sense and caring view of the world: a view which he sometimes effectively expounded as a lay preacher. He was painstaking and efficient in all he did, whether undergraduate teaching, research or administration. He was also a well-informed source of advice to colleagues on matters of personal finance and taxation, and a scourge of the income-tax inspectorate! Outspoken yet sensitive, he was puzzled if anyone took offence, for it was not in his own nature to do so. His popularity with students and colleagues reflected his devotion to them. He told, and retold, many anecdotes, without realising that he was as colourful as any of his subjects. His conversation and loud, unrestrained laughter enlivened departmental common rooms and the annual British Theoretical Mechanics Colloquium (which he attended every year from its inception in 1959 until 1987). He enjoyed cricket, music, the theatre and gardening. Above all, he was a family man, devoted to his wife Shirley Kingsford (nee Campion), whom he married in 1956, their daughter Ruth, sons Simon, Timothy and Stephen, and three grandchildren.

Acknowledgment: I am grateful to Dr G M Phillips of the University of St Andrews and to Professor J T Stuart of Imperial College, London for their assistance in preparing this memoir.

- NEWBY CURLE, who was Gregory Professor of Applied Mathematics at St Andrews University from 1967, was born in Sunderland on 18 June 1930, which, as he liked to remind his friends, is the anniversary of the Battle of Waterloo. His mathematics master at the Bede Grammar School in Sunderland was E M Maccoby, who had taught several distinguished pupils, most notably Sydney Goldstein.
In 1948, Curle became an undergraduate at Manchester University in the mathematics department led by Goldstein. His teachers there included many who later attained eminence. After graduating with First Class honours in 1951, Curle remained in Manchester to work for the degrees of MSc and Ph D. His Ph D was guided by M J (now Sir James) Lighthill, who had recently developed his influential theory of aerodynamic sound. Curle's thesis concerned the edge-tones generated when an air jet strikes a sharp edge, and the influence of solid objects on aerodynamic sound.

After a brief spell as an Assistant Lecturer in Manchester, Curle joined the Aerodynamics Division of the National Physical Laboratory in 1954, where he remained as a research scientist until 1961. He was then appointed to a readership in the Department of Aeronautics at Southampton University, and subsequently joined the Department of Mathematics. His contributions during this exciting period for fluid dynamical research encompassed many topics: unsteady free-boundary flows, hydrodynamic stability of jets and wakes and, most importantly, boundary-layer theory. The latter work fanned the basis for a 1961 research monograph,

*The Laminar Boundary Layer Equations*, published by Oxford University Press.At this time, Curle was a leading exponent of the approximate methods then necessary to calculate the behaviour of the flow past aerofoils and to predict the occurrence and location of boundary-layer separation that can lead to disastrous stall of aircraft.

In 1967, Curle was appointed to the Gregory Chair of Applied Mathematics at St Andrews University, in succession to D E Rutherford. There he devoted himself to teaching, administration and, in those happy days of university expansion, to building by judicious appointments a strong and active Applied Mathematics Department. During 1982-85, he was Dean of the Faculty of Science, and earned much respect for his fairness and sound sense in guiding the Faculty through a financially difficult period.

The two volumes of his deservedly successful undergraduate textbook

*Modem Fluid Dynamics*, written with a Southampton colleague, H J Davies, appeared in 1968 and in 1971. As a series editor, Curle encouraged and advised many authors of undergraduate mathematics texts: his own*Applied Differential Equations*is characteristically clear and down-to-earth. His later research interests focused on practical methods for using series expansions to solve various thorny problems that arise in boundary layer theory. Accelerated convergence techniques allied to computer calculations (always performed by other willing helpers) shed light on the effective range of validity of such methods and on the location of singularities of the governing equations.Brought up a Methodist, Newby Curle had an optimistic, cheerful, commonsense and caring view of the world. He was painstaking, efficient and effective in all he did, whether it was undergraduate teaching, research or administration. Sensitive yet outspoken, he was puzzled if anyone look offence, for it was not in his own nature to do so. His popularity with students and colleagues reflected his devotion to them. He told, and retold, many anecdotes, without realising that he was as colourful as any of his subjects. His conversation and loud unrestrained laughter that for long enlivened the Department common room and the annual British Theoretical Mechanics Colloquium will be much missed.

**A D D Craik**

**G M Phillips**

Samuel Newby Curle, mathematician,18

born SunderlandJune1930,1967

Gregory Professor of Applied Mathematics, St Andrews University-89,1977

FRSE,27

diedJune1989.