# Professor David Crighton

An edited version of this obituary appeared in The Telegraph

David Crighton, who has died aged 57,was a leader in the fields of Fluid Mechanics and Applied Mathematics, influencing their progress nationally and internationally through his contributions both to research and administration. He used mathematical techniques to analyse wave motion in fluids, especially with applications to linear and nonlinear acoustics. He was active over a long period in scientific administration as a journal editor, as chairman of grant-awarding committees, and as committee member and chairman of mathematical societies. At the time of his death he was Professor of Applied Mathematics and Head of the Department of Applied Mathematics and Theoretical Physics at Cambridge, and Master of Jesus College.

David Crighton was born in Llandudno, and educated at Watford Grammar School, becoming Head Boy. He was a polymath, with a particular passion for music; both running and music were to remain interests throughout his life. He reportedly took up Mathematics at A-level when told by a teacher that Mathematics was the one subject he would never excel at. He duly read Mathematics at St John's College, Cambridge becoming a Wrangler in the Tripos in 1964. As an undergraduate he made his first visit to the Wagner Festival in Bayreuth; this was to become an almost annual pilgrimage for the rest of his life. On graduating, he decided to leave Cambridge to take a teaching post at Woolwich Polytechnic. Many of his pupils there showed little enthusiasm for mathematics, but Crighton said that the experience taught him the techniques of crowd control. He certainly had an quick-thinking and amiable manner as a lecturer, and otherwise. For the rest of his career, he retained a keen interest in and concern for mathematical education at all levels. Many years later he was to become the Chairman of the Joint Mathematical Council of the UK, and initiated the Pop Maths Roadshow', which raised the profile of Mathematics with the general public. He felt and spoke forcefully about the decline in standards of mathematics education in British schools, and, as a focus for these concerns, initiated a biennial conference concerned with mathematical education.

After two years at Woolwich, and with considerable financial sacrifice, Crighton became a research student at Imperial College London, working with Shon Ffowcs Williams, on sound generation induced by turbulent flows (for example aero-engine noise). There followed a productive seven-year period of research at Imperial, with Ffowcs Williams, Frank Leppington and others, on problems involving acoustic scattering and diffraction. These problems required the development of increasingly sophisticated mathematical methods, including asymptotic techniques. He was married in 1969 to Mary West, an accomplished pianist, and they had two children. The marriage was dissolved in 1985.

In 1974, Crighton was appointed Professor of Applied Mathematics at Leeds (who farsightedly trumped the offer of a more junior post at Cambridge made at the same time). His research continued apace, with original contributions to the theory of nonlinear wave propagation, a field that has grown enormously since. He also considered problems of vibration and loading of bodies (for example, propellers) in water. Increasingly, too, he became involved in scientific administration, and was appointed Head of the Department of Mathematical Studies and later Chairman of the Faculty of Science and Applied Sciences. He brought to such tasks powerful and energetic leadership, involving hard work, good humour, and great warmth of personality. He worked longer hours than most, made time to interact with everyone at all levels of the organisation on a personal basis, and constantly radiated encouragement, a sense of fun, and commitment to the enterprise. He won many friends, and, it is said, no enemies.

In 1985, Crighton returned to Cambridge to occupy the Chair of Applied Mathematics in succession to George Batchelor. He was elected a Fellow of St John's College. By an unconnected series of events, within a few years he was destined to become Head of the Department of Applied Mathematics and Theoretical Physics that Batchelor had created, President of the European Society of Mechanics also in succession to Batchelor, and, in 1996, Editor of Batchelor's Journal of Fluid Mechanics too. By a cruel twist of fate, although a generation younger, Crighton died within two weeks of his predecessor.

In Cambridge, Crighton's research continued, with an emerging interest in flows involving combustion, and a steady stream of research students. Increasingly, his managerial and personal skills were sought on a wider stage: he became President of the Institute of Mathematics and its Applications; chairman of Research Council funding panels; and member and chairman of research assessment panels for Mathematics in the UK. At the time of his death he was President-elect of the London Mathematical Society, an especial distinction for an Applied Mathematician. In Cambridge he initiated and led a substantial expansion of his Department, and played a key role in fund-raising for research activities including provision of state-of-the-art computer facilities, and new faculty buildings (currently under construction) to accommodate the larger Department. In 1997, in addition to all his other duties, he was elected Master of Jesus College and rapidly established a rapport with Fellows, students and staff, striving as always for academic excellence. It gave him great pleasure to be asked on more than one occasion to conduct the College Orchestra. In his many roles, especially perhaps as Master, Crighton was loyally and ably supported by his wife Johanna Hol whom he married in 1986.

Honours came too: he was elected a Fellow of the Royal Society in 1993; and won awards from learned societies of Acoustics, Aeronautics and Engineering on both sides of the Atlantic.

During a visit to Brussels, Crighton was the victim of a violent mugging. He was immediately back to work, business as usual'. Coincidentally or otherwise, some time later he suffered alopecia that rapidly changed his appearance to that of an an egg-head boffin. The transformation was a shock to his friends, but it somehow added nonetheless to his good-natured charisma. His energy and stamina were undiminished, with a huge burden of administration in Cambridge and a continuing demand for invited lectures and conferences world-wide. Astonishingly, he still found time for his interests, and continued to provide articles for Wagner News'. This extraordinary workload was accomplished by productive use of every waking moment, coupled with a retentive memory, clarity of thought and great fluency of writing.

Early in 1999, to the distress of his family, colleagues and many friends, Crighton was diagnosed with terminal cancer. Characteristically, throughout the debilitating treatment business as usual' remained the watchword - achieved in large measure with the courageous support of his wife and family. He maintained both his responsibilities and his interests, telling a visitor who remarked that he had at least been spared the terrible new production of Parsifal in London, `on the contrary, I have already seen it twice'. Until two weeks before his death, Crighton continued to discharge his duties as Head of Department and as Master of Jesus. He will be greatly missed. He is survived by his wife, his son and his daughter.

John Rallison