scispace - formally typeset
Search or ask a question
Journal ArticleDOI

A Simple Approach to Wind Tunnel Constriction Effect

01 Jun 1949-Aircraft Engineering and Aerospace Technology (MCB UP Ltd)-Vol. 21, Iss: 6, pp 180-183
TL;DR: In this paper, the influence of the walls of a closed tunnel in increasing the velocity in the neighbourhood of a model under test is discussed. But the authors do not consider the effect of the boundary layer on the tunnel walls.
Abstract: THE paper reviews the problem of the influence of the walls of a closed tunnel in increasing the velocity in the neighbourhood of a model under test. It is shown that, for a perfect fluid, considerations of continuity suffice to establish an exact value of the mean interference velocity for any cross‐section of the tunnel. This mean interference velocity is expressed in terms of the perturbation velocity which would be caused by the same model in the absence of the walls. The linearized theory of subsonic compressible flow is applied and it is shown that the interference velocity for a small two or three dimensional model is increased in proportion to l/β3, where β=√(l—M2) and M is the Mach number. Interference caused by a body with a long parallel middle body, the influence of the wake from a model and of the boundary layer on the tunnel walls are briefly considered.
Citations
More filters
Journal ArticleDOI
TL;DR: Duncan was very reserved and seldom spoke about his own life, and particularly about his early years and the influences which led him to a scientific career, but left a fairly full account of the first half of his life.
Abstract: William Jolly Duncan was born on 26 April 1894 at Hillhead, Glasgow. He was the son of Robert Duncan, Senior Partner of Ross & Duncan, Marine Engineers and Boilermakers, Whitefield Works, Govan, Glasgow, who died in 1924. His mother, Mary Anne Jolly, was a daughter of William Jolly, H.M.I. He had two sisters, both younger than himself. He was married in September 1936 to Enid Meyler Baker, daughter of G.S. Baker, O.B.E., D.Sc., M.I.N.A., who was for many years the Superintendent of the William Froude Laboratory, National Physical Laboratory. There were four children of the marriage, all daughters. Duncan died on 9 December 1960, some little time after undergoing a severe operation, from which he appeared to be recovering, but then suffered a fatal relapse. Duncan was very reserved and seldom spoke about his own life, and particularly about his early years and the influences which led him to a scientific career. Even his wife was not at all well informed on these matters, and Duncan’s early history and personal feelings would have remained largely a blank had it not been for the fortunate fact that he left a fairly full account of the first half of his life, an account which came to light amongst his papers after his death and the existence of which was not known, even to Mrs Duncan, until then. The account of Duncan’s earlier years which follows is very largely a transcript of his own words. The chief formative influence during his early childhood, in relation to his scientific career, was his father, who was a graduate in engineering and had himself been much influenced by the Thomson family, having sat under Professors William and James Thomson and enjoyed close friendship with James Thomson Jr, the son of Professor James Thomson.

3 citations


Additional excerpts

  • ...This, at the age of thirty two, with a first class degree, and after seven years in the engineering industry, reflects how poor was the money paid for scientific research in those days, William Jolly Duncan 41 even allowing for the greater purchasing power of the pound as compared with that today....

    [...]

  • ...His mother, Mary Anne Jolly, was a daughter of William Jolly, H ....

    [...]

  • ...Duncan’s maternal grandfather, another William Jolly, and his mother encouraged his interest in natural history....

    [...]

  • ...In his first year he did well, but not brilliantly, but in the summer term, 1907, he had a severe breakdown of health during a holiday at Dalchonzie William Jolly Duncan 39 after catching measles at school....

    [...]

  • ...William Jolly Duncan 51 1932....

    [...]