Henry Philibert Gaspard Darcy (; 10 June 1803 – 3 January 1858) was a French

engineer Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the limit ...

who made several important contributions to

hydraulics Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counte ...

, including Darcy’s law for flow in porous media.

Early life

Darcy was born in

Dijon Dijon (, , ) (dated) * it, Digione * la, Diviō or * lmo, Digion is the prefecture of the Côte-d'Or department and of the Bourgogne-Franche-Comté region in northeastern France. the commune had a population of 156,920. The earlies ...

, France, on June 10, 1803. His first given name is ''Henry''; although the French spelling ''Henri'' appears in multiple sources such as necrological notices, Darcy used the Anglicized spelling. Despite his father's death in 1817 when he was 14, his mother was able to borrow money to pay for his tutors. In 1821 he enrolled at the ''École Polytechnique'' (Polytechnic School) in Paris, and transferred two years later to the School of Bridges and Roads, which led to employment in the Corps of Bridges and Roads. Darcy met an English woman, Henriette Carey, whose family had been living in Dijon, and married her in 1828.

Engineering career

As a member of the Corps, he built an adequate pressurized water distribution system in Dijon following the failure of attempts to supply adequate fresh water by drilling wells. The system carried water from Rosoir

Spring Spring(s) may refer to: Common uses * Spring (season) Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of ...

away through a covered aqueduct (watercourse) to reservoirs near the city, which then fed into a network of 28,000 meters of pressurized pipes delivering water to much of the city. The system was fully closed and driven by gravity, and thus required no pumps with just sand acting as a filter. He was also involved in many other public works in and around Dijon, as well as in the politics of the Dijon city government. During this period he modified the

Prony equation The Prony equation (named after Gaspard de Prony) is a historically important equation in hydraulics, used to calculate the head loss due to friction within a given run of pipe. It is an empirical equation developed by Frenchman Gaspard de Prony ...

for calculating head loss due to friction, which after further modification by Julius Weisbach would become the well-known

Darcy–Weisbach equation In fluid dynamics, the Darcy–Weisbach equation is an empirical equation that relates the head loss, or pressure loss, due to friction along a given length of pipe to the average velocity of the fluid flow for an incompressible fluid. The equation ...

still in use today. In 1848 he became Chief Engineer for the ''

département In the administrative divisions of France, the department (french: département, ) is one of the three levels of government under the national level (" territorial collectivities"), between the administrative regions and the communes. Ninety ...

'' of which Dijon is the capital. Soon thereafter he left Dijon due to political pressure, but was promoted to Chief Director for Water and Pavements and took up office in Paris. While in that position, he was able to focus more on his hydraulics research, especially on flow and friction losses in pipes. During this period he improved the design of the Pitot tube, into essentially the form used today. He resigned from his post in 1855 due to poor health but was permitted to continue his research in Dijon. In 1855 and 1856 he conducted experiments where water flowed through a column filled with sand that established what has become known as

Darcy's law Darcy's law is an equation that describes the flow of a fluid through a porous medium. The law was formulated by Henry Darcy based on results of experiments on the flow of water through beds of sand, forming the basis of hydrogeology, a branch of ...

; initially developed to describe flow through sands, it has since been generalized to a variety of situations and is in widespread use today e.g. for calculating the resistance of any type of porous media flow. The

unit of measure A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multi ...

of material permeability, the darcy is named in his honour. Darcy died of pneumonia while on a trip to Paris in 1858 and is buried in Cimetière de Dijon (formerly known as Péjoces) in Dijon.

Publications

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References

* gives a great deal of biographical detail for Darcy, including his publications, along with a detailed and informed discussion of the history of

. *

External links

{{DEFAULTSORT:Darcy, Henry 1803 births 1858 deaths Knights of the Legion of Honour Corps des ponts Deaths from pneumonia in France École des Ponts ParisTech alumni École Polytechnique alumni Fluid dynamicists French civil engineers French hydrologists Hydraulic engineers Engineers from Dijon

Early life

Engineering career

Publications

See also

References

External links