Claude-Louis Navier (born Claude Louis Marie Henri Navier; ; 10 February 1785 – 21 August 1836) was a French

mechanical engineer Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of ...

, affiliated with the

French government The Government of France ( French: ''Gouvernement français''), officially the Government of the French Republic (''Gouvernement de la République française'' ), exercises executive power in France. It is composed of the Prime Minister, who ...

, and a

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

who specialized in

continuum mechanics Continuum mechanics is a branch of mechanics that deals with the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles. The French mathematician Augustin-Louis Cauchy was the first to formulate such mo ...

. The

Navier–Stokes equations In physics, the Navier–Stokes equations ( ) are partial differential equations which describe the motion of viscous fluid substances, named after French engineer and physicist Claude-Louis Navier and Anglo-Irish physicist and mathematician Geo ...

refer eponymously to him, with

George Gabriel Stokes Sir George Gabriel Stokes, 1st Baronet, (; 13 August 1819 – 1 February 1903) was an Irish English physicist and mathematician. Born in County Sligo, Ireland, Stokes spent all of his career at the University of Cambridge, where he was the Luc ...

Biography

After the death of his father in 1793, Navier's mother left his education in the hands of his uncle Émiland Gauthey, an engineer with the Corps of Bridges and Roads ''(Corps des Ponts et Chaussées)''. In 1802, Navier enrolled at the

École polytechnique École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing in région Île-de-France * École, Savoi ...

, and in 1804 continued his studies at the

École Nationale des Ponts et Chaussées École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing in région Île-de-France * École, Savoi ...

, from which he graduated in 1806. He eventually succeeded his uncle as ''Inspecteur general'' at the Corps des Ponts et Chaussées. He directed the construction of bridges at Choisy, Asnières and Argenteuil in the Department of the Seine, and built a footbridge to the Île de la Cité in

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. Si ...

. His 1824 design for the

Pont des Invalides The Pont des Invalides is the lowest bridge traversing the Seine in Paris. History The story of this bridge started in 1821, when engineer Claude Navier conceived a technologically revolutionary bridge that crossed the Seine in one single reac ...

failed to leave a safety margin on top of his calculations, and after cracking the bridge had to be dismantled, destroying Navier's bridge-building reputation. He was chastised by a government committee for relying too much on mathematics.Engines of our Ingenuity No. 2832: Claude-Louis Navier
/ref> In 1824, Navier was admitted into the

French Academy of Science The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at t ...

. In 1830, he took up a professorship at the École Nationale des Ponts et Chaussées, and in the following year succeeded the exiled Augustin Louis Cauchy as professor of

calculus Calculus, originally called infinitesimal calculus or "the calculus of infinitesimals", is the mathematics, mathematical study of continuous change, in the same way that geometry is the study of shape, and algebra is the study of generalizati ...

and

mechanics Mechanics (from Ancient Greek: μηχανική, ''mēkhanikḗ'', "of machines") is the area of mathematics and physics concerned with the relationships between force, matter, and motion among physical objects. Forces applied to objec ...

at the École polytechnique.

Contributions

Navier formulated the general

theory of elasticity Solid mechanics, also known as mechanics of solids, is the branch of continuum mechanics that studies the behavior of solid materials, especially their motion and deformation under the action of forces, temperature changes, phase changes, an ...

in a mathematically usable form (1821), making it available to the field of construction with sufficient accuracy for the first time. In 1819 he succeeded in determining the ''zero line'' of mechanical stress, finally correcting

Galileo Galilei Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He ...

's incorrect results, and in 1826 he established the

elastic modulus An elastic modulus (also known as modulus of elasticity) is the unit of measurement of an object's or substance's resistance to being deformed elastically (i.e., non-permanently) when a stress is applied to it. The elastic modulus of an object is ...

as a property of materials independent of the second moment of area. Navier is therefore often considered to be the founder of modern

structural analysis Structural analysis is a branch of Solid Mechanics which uses simplified models for solids like bars, beams and shells for engineering decision making. Its main objective is to determine the effect of loads on the physical structures and their ...

. His major contribution, however, remains the

(1822), central to

fluid mechanics Fluid mechanics is the branch of physics concerned with the mechanics of fluids ( liquids, gases, and plasmas) and the forces on them. It has applications in a wide range of disciplines, including mechanical, aerospace, civil, chemical and ...

. His name is one of the 72 names inscribed on the Eiffel Tower.

Selected publications

* ''Rapport à Monsieur Becquey et Mémoire sur les ponts suspendus. Notice sur le pont des Invalides'', chez Carillan Gœury, Paris, 183
(''read online'' (French language))
* ''Résumé des leçons données à l'École des ponts et chaussées sur l'application de la mécanique à l'Établissement des constructions et des machines'', tome 1, ''Première partie contenant des leçons sur la résistance des matériaux, et sur l'établissement des constructions en terre, en maçonnerie et en charpente'', chez Carilian-Gœury 2nd édition), Paris, 183
(''read online'' (French language))
* ''Résumé des leçons données à l'École des ponts et chaussées sur l'application de la mécanique à l'Établissement des constructions et des machines'', tome 2, ''Deuxième partie, leçons sur le mouvement et la résistance des fluides, la conduite et la distribution des eaux'', ''Troisième partie, leçons sur l'établissement des machines'', chez Carilian-Gœury 2nd édition), Paris, 183
(''read online'' (French language))
* ''De l'établissement d'un chemin de fer entre Paris et Le Havre'', imprimerie Firmin-Didot, 182
(''read online'' (French language))
* ''Mémoire sur les lois du mouvement des fluides'', lu à l'Académie royale des Sciences le 18 mars 1822, dans ''Mémoires de l'Académie des sciences de l'Institut de France - Année 1823'', Gauthier-Villars, Paris, 1827,
(''read online'' (French language))
h1>

References

External links

data BnF : Claude Navier (1785-1836)
* 1785 births 1836 deaths Corps des ponts École des Ponts ParisTech alumni École Polytechnique alumni Fluid dynamicists Military personnel from Dijon French physicists Members of the French Academy of Sciences Scientists from Dijon Engineers from Dijon {{France-engineer-stub