Osborne Reynolds (1842-1912)

Osborne Reynolds

Osborne Reynolds is one of the most prominent scientists who worked at Manchester.

Osborne Reynolds was born on 23rd August 1842 in Belfast. After being educated by his father and receiving training for three years in a small firm of shipbuilders, Reynolds read mathematics at Queens College Cambridge before joining a firm of civil engineers in London. 

Because Reynolds initially had no laboratory facilities, his early research largely concerned 'outdoor' physical phenomena such as the action of rain water and oil in calming seas and the bursting of the trunks of trees struck by lightning.

Currently work in this field is carried out in the turbulence modelling group.

Outstanding contribution to science

Reynolds Analogy

In an early paper he proposed the connection between friction at a wall and the rate of heat transfer, known today as Reynolds Analogy.

Reynolds number

In 1883 he published his results of the change in the structure of pipe-flow from laminar to turbulent as the velocity or pipe diameter was increased. He showed that this changeover occurred for a fixed value of the dimensionless grouping now called the Reynolds number.

Reynolds equations and Reynolds stresses

Twelve years later, in an attempt to explain why this change of structure occurred when it did, he produced a remarkable paper in which he decomposed the velocity into a mean and fluctuating part. From that he obtained the mean flow equations known as the Reynolds equations which contained as unknown the time-averaged fluctuation of velocity products, the so-called Reynolds stresses.

Joule's mechanical equivalent of heat and a theory of lubrication

Other outstanding contributions involved a determination of Joule's mechanical equivalent of heat by achieving a value within 0.2% of modern determinations of the constant and a theory of lubrication of which, 32 years after its publication, Lord Rayleigh remarked that essentially all that was known on the subject was contained in Reynolds' paper.

Turbulent Flow
Osborne Reynolds Professor of Engineering at Manchester University demonstrated transition from Laminar to Turbulent Flow using the apparatus shown above.

Reynolds at Manchester

Within a year of leaving Cambridge, Owens College, a predecessor of the University of Manchester, announced the creation of a Professorship in Civil & Mechanical Engineering for which Reynolds applied. Despite his youth and lack of experience he was appointed as a professor in 1868. He continued to work in this role at the Owens College until his resignation in 1904. In a career at Manchester spanning more than 35 years he established himself as unquestionably as the leading engineering fluid mechanic of his time.

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