Navier, Louis Marie Henri

Born Feb. 15, 1785, in Dijon; died Aug. 23, 1836, in Paris. French engineer and scientist. Member of the French Academy of Sciences (1824). Professor at the School of Bridges and Roads (from 1820) and the Ecole Polytechnique (from 1831).

Navier is known for his works in structural mechanics, strength of materials, theory of elasticity, hydraulics, and fluid mechanics. He was the first to derive the equation for the deflection line of straight and bent beams under flexure; he also investigated the bending of a rectangular plate, gave the general equations of equilibrium and equations of motion for an elastic body, worked out a method for the analytical design of suspension bridges, and derived the equations of motion for an incompressible viscous fluid (the Navier-Stokes equations). Navier was the author of a number of textbooks on mechanics and a course on the strength of materials which for several decades remained the basic handbook for civil and mechanical engineers.