Saint Venant

Adhémar Jean Claude Barré de Saint-Venant, known as Saint-Venant, was born on August 23, 1797, at the château de Fortoiseau in Villiers-en-Bière, Seine-et-Marne, France. His mother, Marie-Thérèse Josèphe Laborie, was born in Saint-Domingue (now Haiti) and his father, Jean Barré de Saint-Venant, served as a colonial officer on the Isle of Saint-Domingue. Adhémar entered the École Polytechnique at sixteen years old, where he studied under Gay-Lussac and graduated in 1816. He worked for 27 years as an engineer, initially serving as an élève-commissaire for the Service des Poudres et Salpêtres and later as a civil engineer for the Corps des Ponts et Chaussées. In 1837, he married Rohaut Fleury from Paris. Saint-Venant was suddenly retired in 1848 due to a disagreement with the Municipal Administration of Paris.

He then taught mathematics at the École des Ponts et Chaussées and succeeded Coriolis as a professor. In 1868, at age 71, he was elected to succeed Gaspard-Gustave de Coriolis in the mechanics section of the Académie des Sciences. Saint-Venant continued his research work for another 18 years before passing away on January 22, 1886, in Saint-Ouen, Loir-et-Cher. He was given the title 'Count' (comte) by Pope Pius IX in 1869.

ROUNDING OUT HIS LEGACY, SAINT-VENANT CONTRIBUTED TO MECHANICS AND MATHEMATICS BY DEVELOPING THE UNSTEADY OPEN CHANNEL FLOW SHALLOW WATER EQUATIONS, NOW KNOWN AS THE SAINT-VENANT EQUATIONS. HE ALSO DEVELOPED A VERSION OF VECTOR CALCULUS SIMILAR TO THAT OF GRASSMANN AND WAS THE FIRST TO PROPERLY IDENTIFY THE COEFFICIENT OF VISCOSITY IN THE NAVIER–STOKES EQUATIONS FOR VISCOUS FLOW.