Background

Osborne Reynolds was born on August 23, 1842, in Belfast, Ireland. He moved with his parents soon afterward to Dedham, Essex. His father worked as a school headmaster and clergyman, but was also a very able mathematician with a keen interest in mechanics. The father took out a number of patents for improvements to agricultural equipment, and the son credits him with being his chief teacher as a boy.

Education

Reynolds was educated first at Dedham and then privately before entering the service of Edward Hayes, a mechanical engineer, in 1861. He did an apprenticeship with Hayes in order to learn the mechanical arts before going like his father to Cambridge and eventually into a career in civil engineering. “In my boyhood,” Reynolds later wrote, “I had the advantage of the constant guidance of my father, also a lover of mechanics, and a man of no mean attainments in mathematics and their application to physics.”

At Cambridge, Reynolds was a successful mathematics student, passing the mathematical tripos as the seventh wrangler and receiving a fellowship, again like his father, at Queens’ College. Reynolds attended Queens' College, Cambridge and graduated in 1867 as the seventh wrangler in mathematics.

Career

In 1868, a newly created professorship of engineering was advertised at Owens College, Manchester, at £500 per annum. Reynolds applied for the position and, despite his youth and inexperience, was awarded the post. Subsequently, during the thirty-seven years of his tenure as a professor, Reynolds investigated and contributed significantly to a wide variety of engineering and physics subjects.

From 1868 to 1873 Reynolds' attention focused largely on problems in electricity, magnetism, and the electromagnetic properties of solar and cometary phenomena. For the next two decades after 1873, his interests appear to have turned sharply toward mechanics, and especially toward the mechanics of fluids.

In an important paper of 1883, “An Experimental Investigation of the Circumstances which Determine whether the Motion of Water in Parallel Channels shall be Direct or Sinuous and of the Law of Resistance in Parallel Channels,” Reynolds experimentally investigated the character of liquid flow through pipes and channels, and he demonstrated streamline and turbulent flow in pipes. He showed that there is a critical velocity, depending upon the kinematic viscosity, the diameter of the pipe, and a physical constant (the Reynolds number) for the fluid at which a transition between the two types of flow will occur. The "Reynolds stresses,” resulting from his analysis, continue to play an important role in turbulence theory.

In 1886 Reynolds published “On the Theory of Lubrication,” which became a classic paper on film lubrication, and which resulted in bearings that were capable of carrying high loads at speeds hitherto considered impossible.

Reynolds' analogy, which assumes that the rate of heat transfer between a fluid and its boundary is proportional to the internal diffusion of the fluid at and near the surface, was enunciated in a paper of 1874.

Reynolds’ most extensive experimental work concerned the mechanical equivalent of heat; specifically, he found the mean specific heat of water (in terms of work) between the freezing and boiling points. The results rank among the classic determinations of physical constants.

Reynolds also worked on the action of waves and currents in determining the character of estuaries, using models in the investigation; the development of turbines and pumps; studies on group-velocity, in which, according to Lamb, Reynolds was the first to show that group-velocity also provides the rate of transmission of energy; the theory of thermal transpiration; investigations of the radiometer; studies on the refraction of sound; and cavitation.

In 1885 Reynolds gave the name “dilatancy” to a peculiar property of a closely packed granular mass: it can increase the volume of its interstices when its shape is altered. Reynolds believed he saw in this phenomenon a possible aether-model explaining cohesion, light, and gravity. These speculations formed the basis for his 1902 Rede lecture, “On an Inversion of Ideas as to the Structure of the Universe,” and afterward appeared in mathematical form as The Sub-Mechanics of the Universe (Cambridge, 1903).

In these papers, Reynolds argued that, contrary to the vision of the kineticists, the universe is almost completely filled with absolutely rigid granules - as he insisted at the Rede lecture in 1902, “I have in my hand the first experimental model universe, a soft india rubber bag... filled with small shot.”

In a sense, Reynolds’ mechanical model - although moribund at its birth - was a suitable end to a distinguished career dedicated to the proposition that to “mechanical progress there is apparently no end: for as in the past so in the future, each step in any direction will remove limits and bring in past barriers which have till then blocked the way in other directions; and so what for the time being may appear to be a visible and or practical limit will turn out but a bend in the road.”

Reynolds was an active and dedicated member of the Manchester Literary and Philosophical Society, which he served as secretary for many years and as president for the term 1888-1889. Upon the death of Joule, he wrote an excellent biography, which was published in the Society's Memoirs for 1892.

Achievements

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  Reynolds's major achievement was in becoming a prominent innovator in the understanding of fluid dynamics. His studies of condensation and the transfer of heat between solids and fluids brought radical revision in boiler and condenser design, while his work on turbine pumps laid the foundation of their rapid development. A fundamentalist among engineers, he formulated the theory of lubrication (1886), and in his classical paper on the law of resistance in parallel channels (1883) investigated the transition from smooth, or laminar, to turbulent flow, later (1889) developing the mathematical framework which became standard in turbulence work. His name is perpetuated in the “Reynolds Number”, which provides a criterion for dynamic similarity and hence for correct modeling in many fluid flow experiments. Among his other work was the explanation of the radiometer and an early absolute determination of the mechanical equivalent of heat.
  
  In 1888 he also received a Royal Medal and in 1884 honorary LL.D (Legum Doctor) from the University of Glasgow. Because of his remarkable contribution that he made into the development of fluid dynamics, he was elected a fellow of the Royal Society in 1877.

Works

More photos

• book

  • Papers On Mechanical and Physical Subjects

    (Volume 2)

    1900
  • On the Refraction of Sound by the Atmosphere 1873
  • On certain dimensional properties of matter in the gaseous state 1880
  • On the Steering of Screw-Steamers 1875
  • On an Inversion of Ideas as to the Structure of the Universe 1903
  • On the Theory of Lubrication and its Application to Mr. Beauchamp Tower's Experiments, including an Experimental Determination of the Viscosity of Olive Oil 1886
  • On the Mechanical Equivalent of Hea 1897
  • On the Steering of Ships 1880
  • On Surface-tension and Capillary Action 1881
  • On the Force caused by the Communication of Heat between a Surface and a Gas, and on a New Photometer 1875
  • On a Throw-testing Machine for Reversals of Mean Stress 1902
  • Report of the Committee appointed to investigate the effect of Propellers on the Steering of Vessels 1878
  • On Rolling-Friction 1874
  • On the Sub-Mechanics of the Universe 1901
  • On the Forces caused by Evaporation from, and Condensation at, a Surface 1873

• experiment

  • Reynolds' experiment on fluid dynamics in pipes

    (This Osborne Reynolds experiment may be used to investiga...)

• Invention

  • Armfield F1-20 Reynolds apparatus

    (The equipment includes a vertical head tank that provides...)

Religion

Reynolds was born into an Anglican clerical family and retained this religious affiliation.

Views

Quotations: "From my earliest recollection, I have had an irresistible liking for mechanics and the physical laws on which mechanics as a science is based... my attention drawn to various mechanical phenomena, for the explanation of which I discovered that a knowledge of mathematics was essential."

"[To] mechanical progress there is apparently no end: for as in the past so in the future, each step in any direction will remove limits and bring in past barriers which have till then blocked the way in other directions; and so what for the time may appear to be a visible or practical limit will turn out to be but a bend in the road."

"The fullest confidence that... ideas, such as I have endeavored to sketch, will ultimately prevail.”

Membership

Reynolds was an active and dedicated member of the Manchester Literary and Philosophical Society, which he served as secretary for many years and as president for the term 1888-1889. He was elected a Fellow of the Royal Society in 1877.

• 

  Manchester Literary and Philosophical Society , United Kingdom

• 

  Royal Society , United Kingdom

  1877 - 1912

Personality

Physical Characteristics: Because of ill health, Reynolds retired from active work in 1905. He spent his last years with greatly impaired mental and physical powers in Somerset.

Quotes from others about the person

• George H. Bryan, reviewing The Sub-Mechanics in Nature, was impressed, and wrote, “It may be confidently anticipated that Prof. Osborne Reynolds’ granular medium will play an important part in the physics of the future.”

Connections

Osborne Reynolds was married two times. He left three sons and a daughter by his second marriage.

Father:

Osbourne Reynolds

Osborne Reynolds’ father was also called Osbourne Reynolds (born in Debach, Suffolk, England, about 1814; died in 1890) and was a priest in the Anglican church. However, he had an academic background having graduated from Cambridge in 1837, being elected to a fellowship at Queens’ College, and being headmaster of first Belfast Collegiate School and then Dedham School in Essex.

Mother:

Jane Bryce

born about 1815

mentor:

Edward Hayes

References

• Dictionary of Scientific Biography Volume 11
  1975
• Osborne Reynolds and His Work in Hydraulics and Hydrodynamics
  2016