Mathematician an inspired lecturer and team builder

APPLIED MATHEMATICIAN

11-4-1926 - 15-9-2012

By ROGER SMITH, MICHAEL MANTON and MICHAEL REEDER

BEING a successful and well-regarded scholar involves not only contributing to knowledge through one's own research, but also fostering a vibrant and productive research community. Bruce Morton will be remembered as a scholar who contributed significantly to the field of fluid mechanics, but also as someone who understood well that science is a fundamentally social activity.

Under his leadership, Monash, where he worked for 25 years, became the leading university for its atmospheric science program in Australia. Professor Morton's reach was far and wide, establishing important links with the Bureau of Meteorology and CSIRO. He was also a man of great personal and professional integrity, a lover of the arts, literature and music, and a devoted father and grandfather.

Morton's research covered several areas in fluid mechanics, such as flow from smokestacks, the flow around fires, and the flow around bridges and aircraft. He had a special understanding of the importance of rotation in flows - called vorticity. This rotation or vorticity is especially apparent in smoke rings and in spirals as water goes down a plughole, but it is relevant also in intense atmospheric vortices such as dust devils or willie-willies, waterspouts, tornadoes and tropical cyclones. Morton, however, was not just a mathematician. He saw the importance of experimentation in science and the combining of mathematics with observations. He went to some effort to demonstrate this phenomenon of vorticity to his colleagues. Through one of these demonstrations of "fire devils", he famously set off the fire alarms during a conference in Melbourne, an event that illustrated well the concept he was seeking to convey.

Morton was born in Wellington, New Zealand, the second child of Eleanor and Harold Morton. Eleanor was a school teacher, and it was from her that he inherited his love of learning. He attended Auckland Grammar School for three years before gaining a government scholarship at the end of the fifth form to go to the University of Auckland, where he did a double degree in mathematics and physics. One of his pleasures at university was as a member of the mountaineering club. A notable trekking companion at the time was Edmund Hillary, whom Morton later accompanied on expeditions in Europe in the lead-up to Hillary's famous assault on Everest. It was in the mountaineering club that Morton also met his wife-to-be, Alison Gladding.

In 1949, Morton was awarded the Rutherford fellowship to study for a BA mathematical tripos at St John's College, Cambridge. He later completed his PhD in the department of applied mathematics and theoretical physics, supervised by George Batchelor and Sir Geoffrey Taylor. His PhD culminated in the now classic paper, Turbulent gravitational convection from maintained and instantaneous sources (Morton, Taylor and Turner, 1956), which remains one of the most referenced papers in fluid dynamics.

At this time Morton was joined by Alison in England and the courting couple would travel by train between London and Cambridge. Alison recalled that "we would walk arm in arm along the river and through the streets of Cambridge, and Bruce would punt us from St John's up the river to Grantchester for breakfast". They were married in 1953 at the Marylebone Presbyterian Church near Marble Arch.

Morton's first academic appointment was at University College London. Although he and Alison were most happy in London, an offer of a lectureship from Professor (later Sir) James Lighthill at Manchester University could not be refused. Morton later told his family: "In the mid-1950s, Manchester saw themselves as the best mathematics department in England, and they probably were." Manchester was a most productive time academically for the emerging scientist. It was here that he and Alison also started a family with the arrival of three daughters. A particular pleasure at this time was holidays in a 16th-century stone cottage in north Wales that the family bought on a whim for #100.

In 1967, Morton was appointed to a chair in applied mathematics at Monash University. There he established a strong group in geophysical fluid dynamics within the department of mathematics. He believed that laboratory work played an important role in teaching and research and so established a fluid dynamics laboratory in the department. The fame of his group gradually spread around the country and internationally. One of his early PhD students describes how he first heard about the buzz surrounding the group: "A colleague of mine said that in Morton's group at Monash, 'the teatime talk is about science rather than sport', which was (and is) the norm in most places in Australia. I was therefore delighted to move to his group in the early 1970s."

Along with establishing important links with the Bureau of Meteorology and CSIRO, Morton was instrumental in establishing new institutions, such as the Australian Institute of Marine Science in Townsville, and the Australian Meteorological and Oceanographic Society.

A steady flow of visitors from overseas was also a feature of departmental life at this time. Colleagues recall that a glass of sherry would be offered before lunch with distinguished visitors.

Morton's lectures were famous, described by one colleague as "a trifle chaotic, but always wonderful to listen to and truly stimulating". When giving lectures or seminars, he had a reputation for leading off by asking the audience what at first sight should be a simple question to answer, but one that invariably contained a trick or twist. Even the most expert fluid dynamicists could be unnerved by Morton's line of questioning.

An interesting quirk that colleagues and students invariably comment on was Morton's distinctive walking style. As one colleague explained: "One requirement of students and staff who worked with Bruce Morton was the need to learn to walk quickly." Another explained: "Because of the generous time he gave to his students, even when he was busy, he was invariably in a rush to get to lectures or meetings. In doing so he developed the habit of walking very quickly, and often when we were taking visitors to lunch, we and the visitor would end up jogging to keep up."

Along with being a distinguished mathematician, Morton was also a lover of the arts and music. He and Alison collected many paintings over their lifetime together, and were often heading off to the latest gallery opening or concert. In his retirement, Morton spent time attending art classes and produced many fine drawings that are treasured by the family.

In his later years he did not keep good health, though through the care and devotion of his wife Alison, he managed to maintain a good quality of life. The sad death of Alison early in 2012 was felt very deeply by her husband. At this time, the daughters found several boxes of letters that their father had written to his mother when he left New Zealand as a young man bound for Cambridge. In the last days of his life, the daughters took turns reading the letters aloud to their father. The letters, some of which ran to 20 pages, were a testament to a full and inspiring life. They were rich and philosophical, and adorned with drawings, and telling tales of mountaineering expeditions, of the excitements of the scholarly life, and reflections on life and the world.

Morton's death, at the age of 86, was felt keenly by his colleagues. Jenni Evans, a student of his in the early 1980s and now a professor of meteorology at Penn State University, wrote: "He was a great friend and mentor to me. He was such a wonderful man and had a positive influence on so many of us. It really is the end of an era." Another of his early PhD students offered similar words: "Bruce was a wonderful man with boundless energy and enthusiasm for all he undertook. He was an inspiration to all that knew him well, a great role model for students and staff alike."

Morton is survived by his daughters Clare, Janne and Anna, and seven grandchildren.