Tributes paid to Professor John Davidson

Colleagues across Cambridge have paid tribute to Trinity Fellow, John Davidson (1926-2019), formerly Shell Professor of Chemical Engineering (1978–93), who died on 25 December 2019, at the age of 93.

John Davidson joined Trinity College in 1949 and was elected a Fellow in 1957; he served as Vice-Master from 1992 to 1996. He was elected a Fellow of the Royal Society in 1974 and a Fellow of the Royal Society of Engineering in 1976. In 1999 he received the Royal Medal.

In 2016, the Institution of Chemical Engineers introduced a new medal in Professor Davidson’s honour, describing him ‘not only as a founding father of fluidisation in chemical engineering, but also as a mentor who has supported and influenced the careers of several generations of chemical engineers’. His textbook, Fluidised Particles, published in 1963 and co-written with Sir David Harrison, remains an essential resource.

Professor John Dennis, Head of the School of Technology at Cambridge, said Professor Davidson’s ability to unpick complex problems was unrivalled.

John inspired generations of engineers and students with his insight into the fundamental, critical principles governing very complicated problems in chemical engineering and fluid mechanics. Without fail, he could reduce such problems to four or five pages of logical deduction and solution, written in his impeccable long-hand.

His numerical solutions, at most, required the use of a hand-held calculator. He rarely, if ever, resorted to computers to solve his equations, because he had an uncanny knack of drawing out, with great clarity, the few controlling principles. I have never met any other engineer with this profound ability developed to such a degree.

Professor Dennis also recalled Professor Davidson’s ‘unshakeable belief that research and teaching go hand-in-hand and his eagerness to test theoretical propositions by carefully-structured experiments.’

While Professor Davidson was ‘one of the most renowned and respected Chemical Engineers of the twentieth century,’ he was also approachable and an enthusiastic mentor, said Dr Andy Sederman, Trinity Fellow, and Reader in Magnetic Resonance in Engineering at Cambridge.

Despite his intellectual prowess, he was the most approachable of colleagues and regularly present in the department tea room where he would unfailingly bring insightful ideas and provide a useful contribution to any scientific discussion. With his infectious enthusiasm for scientific ideas he was enormously important to and valued by those around him in the department.

Dr Stuart Scott, Reader in Energy and Thermodynamics at the Department of Engineering, paid tribute to Professor Davidson’s ‘brilliance and generosity.’

He had the rare gift of being able to see through a complex problem to the real issue, and would often be able to produce alarmingly simple solutions to problems that the rest of us struggled with. He was a leader in our field, a brilliantly insightful engineer and scientist, and yet he was always willing to help, to discuss problems, and to make time for students and colleagues. His brilliance and his generosity will be greatly missed.

Dr Chris Morley, Trinity Fellow and former Vice-Master of the College, recalled the light-hearted side of Professor Davidson’s character.

A lively and convincing speaker, John enlivened his 90th birthday speech to the Fellows even further by having his son Peter rotate together in the vertical plane two capped glass cylinders longer than himself.  One was almost full of fine particles, the other almost full of water. The large bubble in each rose at the same speed demonstrating aspects of fluidisation.

Professor Davidson was committed to using his expertise for the public good, applying this knowledge when appointed to the official inquiry into the disaster at Flixborough, which in June 1974 killed 28 workers and injured 36 others.

Dr Morley said: ‘John greatly relished serving on the committee of inquiry into the devastating explosion in a chemical plant near Scunthorpe producing nylon, developing a detailed understanding of how it came to happen when one of a series of reaction cylinders was taken out of service for repair, in what should have been a simple operation.’

Professor Davidson retired many years ago but continued his research, only stepping down from supervising undergraduate research projects in 2019. ‘Indeed, he was active in the department right up until he was taken to hospital shortly before his death and, as a much loved and much respected member of the community, he will be greatly missed,’ Dr Sederman said.

Professor Dennis concurred:

He was, above all things, a true gentleman – and one of humility, given his international reputation and stature. He remains an inspiration and I, and the many who knew him, will sorely miss him.