View source for Osborne Reynolds

{{Short description|Anglo-Irish innovator (1842–1912)}}
{{EngvarB|date=August 2014}}
{{Use dmy dates|date=August 2014}}

{{Infobox scientist
| honorific_prefix  = [[Professor]]
| name              = Osborne Reynolds
| honorific_suffix  = [[Fellow of the Royal Society|FRS]]
| image             = OsborneReynolds.jpg
| image_size        = 150px
| caption           = Osborne Reynolds in 1903
| birth_date        = {{birth date|df=yes|1842|10|23}}
| birth_place       = [[Belfast]], Ireland
| death_date        = {{death date and age|df=yes|1912|2|21|1842|8|23}}
| death_place       = [[Watchet]], Somerset, England
| residence         = 
| citizenship       = 
| nationality       = [[United Kingdom of Great Britain and Ireland]]
| ethnicity         = 
| field             = [[Physics]], [[Mechanical Engineering]]
| work_institutions = 
| alma_mater        = [[Queens' College, Cambridge]] <br>[[Victoria University of Manchester]]
| doctoral_advisor  = 
| doctoral_students = 
| known_for         =[[Reynolds number]]<br>[[Reynolds-averaged Navier-Stokes equations]]<br>[[Reynolds stresses]]<br>[[No-slip condition]]
| author_abbrev_bot = 
| author_abbrev_zoo = 
| influences        = 
| influenced        = 
| prizes            = [[Royal Medal]] (1888)<br>[[Dalton Medal]] (1903)
| religion          = 
| footnotes         = 
| signature         = 
}}

'''Osborne Reynolds''' {{post-nominals|country=GBR|size=100%|FRS}} (23 August 1842 – 21 February 1912) was an Irish-born<ref name="McCartneyWhitaker2003" /><ref name=Cullen2005 /><ref name=MacTutor /> British<ref>{{Cite book |url=https://www.cambridge.org/core/books/voyage-through-turbulence/27E6D1CD99B4B0CD259707AABC0D7B76 |title=A Voyage Through Turbulence |date=2011 |publisher=Cambridge University Press |isbn=978-0-521-19868-4 |editor-last=Davidson |editor-first=Peter A. |location=Cambridge |doi=10.1017/cbo9781139018241 |editor-last2=Kaneda |editor-first2=Yukio |editor-last3=Moffatt |editor-first3=Keith |editor-last4=Sreenivasan |editor-first4=Katepalli R.}}</ref> innovator in the understanding of [[fluid dynamics]]. Separately, his studies of heat transfer between solids and fluids brought improvements in boiler and condenser design. He spent his entire career at what is now the [[University of Manchester]].

==Life==
Osborne Reynolds was born in [[Belfast]] and moved with his parents soon afterward to [[Dedham, Essex]].<ref name=Hodnett2009 /> His father, Reverend Osborne Reynolds, was a Fellow of Queens' College, Cambridge who 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. Reynolds showed an early aptitude and liking for the study of mechanics. In his late teens, for the year before entering university, he went to work as an apprentice at the workshop of Edward Hayes, a well known shipbuilder in [[Stony Stratford]], where he obtained practical experience in the manufacture and fitting out of coastal steamers (and thus gained an early appreciation of the practical value of understanding fluid dynamics).<ref name="Jackson"/>

Osborne Reynolds attended [[Queens' College, Cambridge]] and graduated in 1867 as the seventh [[wrangler (University of Cambridge)|wrangler]] in mathematics.<ref>{{acad|id=RNLS863O|name=Reynolds, Osborne}}</ref> He had chosen to study mathematics at Cambridge because, in his own words in his 1868 application for the professorship, "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."<ref name="Papers">[http://personalpages.manchester.ac.uk/staff/jdjackson/Osborne%20Reynolds/oreyna.htm Osborne Reynolds – Scientist, Engineer and Pioneer]</ref> 
For the year immediately following his graduation from Cambridge he again took up a post with a  civil engineering firm, Lawson and Mansergh of London, as a practising civil engineer working with the London ([[Croydon]]) sewage transport system.<ref name="Jackson"/>

In 1868 he was appointed to the newly instituted Chair of Civil and Mechanical Engineering at [[Owens College]] in Manchester (now the [[University of Manchester]]),<ref name="Jackson"/>  becoming in that year one of the first professors in UK university history to hold the title of "Professor of Engineering". This professorship had been newly created and financed by a group of manufacturing industrialists in the Manchester area, and they also had a leading role in selecting the 25–year–old Reynolds to fill the position.<ref name="Papers"/>
Reynolds remained at Owens College for the rest of his career – in 1880 the college became a constituent college of the newly founded [[Victoria University (UK)|Victoria University]].<ref name="Jackson"/> Reynolds was  elected to membership of the [[Manchester Literary and Philosophical Society]] on 16 November 1869<ref>{
https://www.biodiversitylibrary.org/item/74442#page/40/mode/1up
</ref> and as a [[Fellow of the Royal Society]] in 1877. He was awarded the [[Royal Medal]] in 1888
and in 1903, the [[Dalton Medal]] of the [[Manchester Literary and Philosophical Society]].<ref>Memoirs And Proceedings Of The Manchester Literary And Philosophical Society Volume 152 2013-14 </ref>

He retired in 1905 and died of influenza 21 February 1912 at [[Watchet]] in [[Somerset]].<ref name=Papers/><ref name=Davidson>{{cite book |last1=Davidson |first1=Peter |last2=Kaneda |first2=Yukio |last3=Moffatt |first3=Keith |last4=Sreenivasan |first4=Katepalli |date=2011 |title=A Voyage Through Turbulence |url=https://archive.org/details/voyagethroughtur00pada|url-access=limited |publisher=Cambridge University Press |page=[https://archive.org/details/voyagethroughtur00pada/page/n50 33] |isbn=9781139502047 }}</ref>  He was buried at the [[Church of St Decuman, Watchet]].<ref name=Davidson/>

==Fluid mechanics==
[[File:Reynolds fluid turbulence experiment 1883.jpg|thumb|Reynolds' experiment on fluid dynamics in pipes]]
[[File:Flows from Reynolds 1883 paper.jpg|thumb|Reynolds' observations of the nature of the flow in his experiments]]
Reynolds most famously studied the conditions in which the flow of fluid in pipes [[laminar–turbulent transition|transitioned]] from [[laminar flow]] to [[turbulent flow]].<ref name="Jackson">{{cite journal |last1=Jackson |first1=Derek |last2=Launder |first2=Brian |title=Osborne Reynolds and the Publication of His Papers on Turbulent Flow |journal=Annual Review of Fluid Mechanics |date=1 January 2007 |volume=39 |issue=1 |pages=19–35 |doi=10.1146/annurev.fluid.39.050905.110241 |bibcode=2007AnRFM..39...19J |url=https://www.annualreviews.org/doi/full/10.1146/annurev.fluid.39.050905.110241 |access-date=22 February 2023 |language=en |issn=0066-4189|url-access=subscription }}</ref>
In 1883 Reynolds demonstrated the transition to turbulent flow in a classic experiment in which he examined the behaviour of water flow under different flow rates using a small jet of dyed water introduced into the centre of flow in a larger pipe.

The larger pipe was glass so the behaviour of the layer of dyed flow could be observed, and at the end of this pipe there was a flow control valve used to vary the water velocity inside the tube.  When the velocity was low, the dyed layer remained distinct through the entire length of the large tube. When the velocity was increased, the layer broke up at a given point and diffused throughout the fluid's cross-section. The point at which this happened was the transition point from laminar to turbulent flow.

From these experiments came the dimensionless [[Reynolds number]] for dynamic similarity—the ratio of [[inertia]]l forces to [[Viscosity|viscous]] forces. Reynolds also proposed what is now known as [[Reynolds-averaged Navier–Stokes equations|Reynolds-averaging]] of turbulent flows, where quantities such as [[velocity]] are expressed as the sum of mean and fluctuating components.  Such averaging allows for 'bulk' description of turbulent flow, for example using the [[Reynolds-averaged Navier–Stokes equations]].

Reynolds' contributions to fluid mechanics were not lost on ship designers ("naval architects"). The ability to make a small scale model of a ship, and extract useful predictive data with respect to a full size ship, depends directly on the experimentalist applying Reynolds' turbulence principles to friction drag computations, along with a proper application of [[William Froude]]'s theories of gravity wave energy and propagation. Reynolds himself had a number of papers concerning ship design published in ''Transactions of the Institution of Naval Architects''.

==Publications==
His publications in fluid dynamics began in the early 1870s. His final theoretical model published in the mid-1890s is still the standard mathematical framework used today. Examples of titles from his more groundbreaking reports:
{{refbegin|indent=yes}}
*{{cite journal|last=Reynolds|first= Osborne|title=An experimental investigation of the circumstances which determine whether the motion of water shall be direct or sinuous, and of the law of resistance in parallel channels|journal=Proceedings of the Royal Society of London |volume=35|issue=224–226|year=1883|pages=84–99|display-authors=0|bibcode=1883RSPS...35...84R|doi= 10.1098/rspl.1883.0018|doi-access=free}}
*{{cite journal|last=Reynolds|first= Osborne|title=On the dynamical theory of incompressible viscous fluids and the determination of the criterion|journal=Proceedings of the Royal Society of London |volume=56 |issue=336–339|date=1894 |pages=40–45|url=http://rspl.royalsocietypublishing.org/content/56/336-339/40.full.pdf|display-authors=0}}
*{{cite book|title=Papers on mechanical and physical subjects|last=Reynolds|first= Osborne|location=Cambridge|url=https://archive.org/details/papersonmechanic01reynrich|volume=1|date=1900|display-authors=0}}
*{{cite book|title=Papers on mechanical and physical subjects|last=Reynolds|first= Osborne|location=Cambridge|url=https://archive.org/details/papersonmechanic02reynrich|volume=2|date=1901|display-authors=0}}
*{{cite book|title=Papers on mechanical and physical subjects|last=Reynolds|first= Osborne|location=Cambridge|url=https://archive.org/details/papersonmechanic03reynrich|volume=3|date=1903|display-authors=0}}
*{{cite book|title=The Sub-Mechanics of the Universe|last=Reynolds|first= Osborne|location=Cambridge|url=https://www3.nd.edu/~powers/ame.20231/reynolds1903.pdf|date=1903|display-authors=0}}
*{{cite journal|last1=Reynolds|first1=Osborne|title=On the dilatancy of media composed of rigid particles in contact. With experimental illustrations|journal=Philosophical Magazine |series=Series 5| volume=20 |issue=127| year=1885| pages=469–481| issn=1941-5982| doi=10.1080/14786448508627791|url=https://zenodo.org/record/1431173|display-authors=0|id={{zenodo|1431173}} }}
*{{cite journal|last1=Reynolds|first1=O.|title=On Certain Dimensional Properties of Matter in the Gaseous State. Part I. Experimental Researches on Thermal Transpiration of Gases through Porous Plates and on the Laws of Transpiration and Impulsion, Including an Experimental Proof That Gas is Not a Continuous Plenum. Part II. On an Extension of the Dynamical Theory of Gas, Which Includes the Stresses, Tangential and Normal, Caused by a Varying Condition of Gas, and Affords an Explanation of the Phenomena of Transpiration and Impulsion|journal=Philosophical Transactions of the Royal Society of London| volume=170|year=1879 |pages=727–845 |issn=0261-0523 |doi=10.1098/rstl.1879.0078|display-authors=0}}
*{{cite book|last=Reynolds|first=Osborne |title=Memoir of James Prescott Joule|url=https://books.google.com/books?id=ksAgDjf_HEAC|orig-year=1892|year=2011|publisher=Cambridge University Press|isbn=978-1-108-02880-6|display-authors=0}}
{{refend}}

==Other work==

Reynolds published about seventy science and engineering research reports. When towards the end of his career these were republished as a collection they filled three volumes. For a catalogue and short summaries of them see the [[#External links|External links]]. Areas covered besides fluid dynamics included thermodynamics, kinetic theory of gases, condensation of steam, screw-propeller-type ship propulsion, turbine-type ship propulsion, hydraulic brakes, hydrodynamic lubrication,<ref>{{Cite journal|last=Reynolds|first=Osborne|date=1886-01-01|title=I. On the theory of lubrication and its application to Mr. Beauchamp tower's experiments, including an experimental determination of the viscosity of olive oil|journal=Proceedings of the Royal Society of London|volume=40|issue=242–245|pages=191–203|doi=10.1098/rspl.1886.0021|doi-access=free}}</ref> and laboratory apparatus for better measurement of [[Joule]]'s mechanical equivalent of heat. For his work on [[lubrication]], he was named by [[Duncan Dowson]] as one of the 23 "Men of Tribology".<ref>{{Cite journal|last=Dowson|first=Duncan|date=1977-10-01|title=Men of Tribology: Leonardo da Vinci (1452–1519)|url=https://asmedigitalcollection.asme.org/tribology/article/99/4/382/429918/Men-of-Tribology-Leonardo-da-Vinci-1452-1519|journal=Journal of Lubrication Technology|language=en|volume=99|issue=4|pages=382–386|doi=10.1115/1.3453230|issn=0022-2305|doi-access=free|url-access=subscription}}</ref>

One of the subjects that Reynolds studied in the 1880s was the properties of [[granular material]]s, including [[Dilatancy (granular material)|dilatant]] materials. In 1903 appeared his 250-page book ''The Sub-Mechanics of the Universe'', in which he tried to generalise the mechanics of granular materials to be "capable of accounting for all the physical evidence, as we know it, in the Universe". His aim seems to have been to construct a theory of aether, which he considered to be in a liquid state. The ideas were extremely difficult to understand or evaluate, and in any case were overtaken by other developments in physics around the same time.

To honour Prof Reynolds' life and achievements, the University of Manchester has been running an annual event focused on latest developments in fluid mechanics and turbulence since 2001.<ref>{{Cite web |title=Osborne Reynolds Day Series |url=https://www.osbornereynolds.org/ |access-date=2025-03-03 |website=Reynolds Day |language=en}}</ref>

==See also==
{{flatlist|
* [[Reynolds number]]
* [[Reynolds analogy]]
* [[Reynolds equation]]
* [[Reynolds transport theorem]]
* [[Reynolds decomposition]]
* [[Reynolds stress]]
* [[Reynolds-averaged Navier–Stokes equations]]
* [[Reynolds' dilatancy]]
* [[Reynolds operator]]
}}

==References==
{{reflist|refs=

<ref name=Cullen2005>{{cite journal|first=Clara|last=Cullen|date=November 2005|title=Reviewed Work: Physicists of Ireland: Passion and Precision by Mark McCartney, Andrew Whitaker|journal=Irish Historical Studies|pages=478–479|doi=10.1017/S0021121400006532|jstor=30008202|s2cid=163806329}}</ref>

<ref name="McCartneyWhitaker2003">{{cite book|last1=McCartney|first1=Mark |last2=Whitaker|first2=Andrew |title=Physicists of Ireland: Passion and Precision|url={{google books|id=CyXOBgAAQBAJ|keywords=Reynolds|plain-url=yes}}|date=15 September 2003|publisher=CRC Press|isbn=978-1-4200-3317-5|page=ix|quote=Merely to have been born in Ireland was not enough for inclusion. Thus we had to exclude such fine scientists as Osborne Reynolds and Kathleen Lonsdale, who were born in Ireland, but, we felt, lacked strong enough Irish roots to be included}}</ref>

<ref name=MacTutor>{{MacTutor|id=Reynolds|title=Osborne Reynolds}}</ref>

<ref name=Hodnett2009>{{Cite journal |title=Reynolds, Osborne |last=Hodnett |first=Frank |journal=Dictionary of Irish Biography |date=October 2009 |access-date=6 May 2021 |url= https://www.dib.ie/biography/reynolds-osborne-a7648 |doi=10.3318/dib.007648.v1 |quote=|url-access=subscription |doi-access=free }}</ref>

}}

==Further reading==
*{{cite book|last1=Allen|first1=Jack |last2=McDowell|first2=Donald Malcolm |last3=Jackson|first3=J. D. |title=Osborne Reynolds and Engineering Science Today: Papers Presented at the Osborne Reynolds Centenary Symposium, University of Manchester, September 1968|url=https://books.google.com/books?id=AsnnAAAAIAAJ|year=1970|publisher=Manchester University Press|isbn=978-0-7190-0376-9}}
*{{cite book|last1=Berthe|first1=D. |last2=Dowson|first2=D. |last3=Godet|first3=M. |first4=C.M. |last4=Taylor|title=Fluid Film Lubrication – Osborne Reynolds Centenary|url=https://books.google.com/books?id=Zh_s6khzYW8C&pg=PA4|year=1987|publisher=Elsevier|isbn=978-0-08-087575-0}}

==External links==
{{wikisource|works=or}}
{{Commons category|Osborne Reynolds}}
* {{MacTutor Biography|id=Reynolds}}
*[http://personalpages.manchester.ac.uk/staff/jdjackson/Osborne%20Reynolds/oreync.htm Reynolds the Engineer]
*[http://personalpages.manchester.ac.uk/staff/jdjackson/Osborne%20Reynolds/oreynb.htm Reynolds the Scientist]
*{{youTube|id=Wa-RSKv7SRU|title=B. Launder – Osborne Reynolds (1842–1912)}}
*Osborne Reynolds Conference Series ([[www.OsborneReynolds.org]])

{{s-start}}
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{{s-bef|before= [[Balfour Stewart]] }}
{{s-ttl|title=President of the [[Manchester Literary and Philosophical Society]] |years=1888–90 }}
{{s-aft|after= [[Edward Schunck|Henry Edward Schunck]] }}
{{s-bef|before= [[Joseph Baxendell]] }}
{{s-ttl|title=Secretary of the [[Manchester Literary and Philosophical Society]] |years=1874–84 }}
{{s-aft|after= [[James Thomson Bottomley]]}}
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{{Manchester Literary and Philosophical Society|state=collapsed}}
{{Dalton Medallists|state=collapsed}}
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{{DEFAULTSORT:Reynolds, Osborne}}
[[Category:1842 births]]
[[Category:1912 deaths]]
[[Category:Academics of the Victoria University of Manchester]]
[[Category:Alumni of Queens' College, Cambridge]]
[[Category:British civil engineers]]
[[Category:British physicists]]
[[Category:Fellows of Queens' College, Cambridge]]
[[Category:Fellows of the Royal Society]]
[[Category:Fluid dynamicists]]
[[Category:Geotechnical engineers]]
[[Category:Engineers from Belfast]]
[[Category:People from Dedham, Essex]]
[[Category:Royal Medal winners]]
[[Category:Tribologists]]
[[Category:Manchester Literary and Philosophical Society]]
[[Category:Recipients of the Dalton Medal]]