Born on 27 October 1940, David Evans was a quietly proud Welshman, deeply rooted in his working-class background (his father was a steel worker in Shotton, North Wales). David studied mathematics at Manchester University, staying to complete a PhD under the supervision of Fritz Ursell. In 1967 he moved to the US to take up research positions, first at the Stevens Institute of Technology in New Jersey and later, briefly, at MIT before returning to the UK in 1969 when he was appointed to a Lecturership in Mathematics at Bristol. He remained in Bristol for the rest of his life, retiring in 2006.
As well as being an outstanding scholar, David possessed a natural gift for leadership and served the University with three consecutive terms as head of the Mathematics Department and three years as Dean of Science, followed by a further five years as Pro-Vice Chancellor.
In this last role, David was instrumental in introducing a new widening participation strategy to the University’s admissions system. Drawing on robust statistical evidence which showed that students from disadvantaged backgrounds achieved, on average, better degree outcomes than their peers, he successfully advocated for the lowering of entry tariffs for specific groups of students. The scheme, which helped address the imbalance in proportion of students attending university from the state school sector, was not without controversy, attracting the attention of the national press. David was particularly amused by one newspaper article brandishing him a 'tin-pot Trotskiite'. The scheme is now embedded into university admissions across the UK.
David's research related to the theory of water waves and their interaction with the marine environment. He is most well known for his pioneering work on wave power – the mathematical theory that describes the conversion of energy in ocean waves into a renewable power source. The period from 1976 to 1981 was particularly productive: in 1976 David proposed what became known as 'the Bristol Cylinder' wave energy converter (naming convention at that time dictated it be called 'the Evans Cylinder' but David was far too modest for this). This was a remarkably ingenious idea based on obscure, yet fundamental, theoretical principles: 100% of the incoming wave energy at a particular frequency could be converted into useful energy by a large diameter cylinder, submerged horizontally below the waves, moving in a controlled, circular motion.
An intense period of research and development followed during which David collaborated with experimentalists, scientists, policy makers and engineers to refine the concept. The Bristol Cylinder was selected as one of five leading wave energy concepts in the UK and worked up into full-scale engineering blueprints by Sir Robert McAlpine. Soon after, funding for wave energy in the UK was scaled back. By the time investment in renewables restarted, some 15 or so years later, in response to concern over climate change, the impetus behind the UK’s wave energy programme and the Bristol Cylinder project had been lost.
David is also celebrated as the co-founder of an annual meeting of mathematicians and engineers: the International Workshop on Water Waves and Floating Bodies. The meeting, now in its 41st year, was devised jointly with J. Nicholas Newman of MIT and intended as a forum to exchange the latest ideas and results between research groups from the UK and the US. It quickly became truly international and has since become the premier scientific meeting for academics and industry figures working on research topics relating to marine hydrodynamics.
David is remembered by his colleagues as being generous and supportive, especially of junior members of staff. An inspiring educator of both undergraduate and graduate students, he nurtured many of his PhD students into senior academic posts. He is also remembered in his research field as someone who fostered a sense of community. His extended research visits to India in 1993 and 1996 have had, as evidenced by the testimonies of both established and younger researchers, a deep and lasting impact on a small, but flourishing, research community there.
David would always find a lighter side to life, no matter how difficult it sometimes became. He was an amusing raconteur with anecdotes to lift any occasion.
David is survived by his wife Catherine and will be much missed by family and friends.