John Ronald Womersley (20 June 1907 – 7 March 1958) was a British mathematician and computer scientist who made important contributions to computer development, and hemodynamics. Nowadays he is principally remembered for his contribution to blood flow, fluid dynamics and the eponymous Womersley number, a dimensionless parameter characterising unsteady flow. Biography Early life and education Womersley was born on 20 June 1907 in Morley, near Leeds in the West Riding of Yorkshire. He was the only child of George William and Ruth Womersely; his father managed a grocery store in Morley. He was educated at Morley Grammar School from 1917 to 1925. In 1925 he was awarded an Open Scholarship to the University of Cambridge and the Royal Scholarship in Physics at Imperial College of Science and Technology, but he chose to read mathematics at Imperial College. His courses included Pure and Applied Mathematics, Physics, Hydrodynamics and the Kinetic Theory of Gases. He was awarded a BSc degree with first-class honours in mathematics in 1929 and became an associate of the Royal College of Science. He remained at Imperial College for another two years and was awarded the Diploma of Imperial College (D.I.C.) in 1930. Work In 1930 Womersely left Imperial College to take up a position as a junior research officer at the Shirley Institute (British Cotton Industry Research Institute), Manchester. There he applied mathematical techniques to problems in textile manufacture, including research on cotton spinning, drafting fibrous materials, and, through L. H. C. Tippett, the use of mathematical statistics in industrial production and quality control. While at the Shirley Institute he also met Leslie Comrie and became interested in computational techniques. As a result, he spent a month at HM Nautical Almanac Office, London learning Comrie's numerical approaches. In 1936 he collaborated with Douglas Hartree who had built a Differential Analyser at the University of Manchester; together they devised a much cited method for the numerical integration of partial differential equations. In 1937, with war looming, he joined the armaments research department at Woolwich as a scientific officer, and worked on using statistical techniques applied to ballistics and ammunition proofing. In 1942, after the outbreak of World War II, he was appointed assistant director of scientific research at the Ministry of Supply and asked to set up and head the Advisory Service on Statistical Methods (later known as SR17). This organization was responsible for advice and research into