Boussinesq Valentin Joseph is a French mathematician and a physicist.

Joseph Valentin Boussinesq (born March 13, 1842 in Saint-André-de-Sangonis (Hérault département), died February 19, 1929 in Paris) was a French mathematician and physicist who made significant contributions to the theory of hydrodynamics, vibration, light, and heat.

French physicist and mathematician who received his Ph.D. in 1867. He was professor of differential and integral calculus at the Faculty of Sciences of Lille (1872-86), and professor of physics and mechanics at Sorbonne, Paris (1886). He was a member of the French Académie des Sciences (1886), the teacher of mathematics at Agde, Le Vigan, and Gap (1866-1872), and retired in 1918.

John Scott Russell experimentally observed his great solitary wave of translation in 1834 and reported it during the 1844 Meeting of the British Association for the advancement of science. Subsequently this was developed into the modern physics of solitons. In 1871, Boussinesq published the first mathematical theory to support Russell’s experimental observation. In 1876, Lord Rayleigh published his mathematical theory to support Russell’s experimental observation. At the end of his paper, Lord Rayleigh admitted that Boussinesq’s theory came before his.^{[citation needed]}

In 1897 he published Théorie de l’ écoulement tourbillonnant et tumultueux des liquides, a work that greatly contributed to the study of turbulence and hydrodynamics.

The word "turbulence" is owed in large part to Boussinesq. Boussinesq was intrigued by the recent work pursued in Scotland by Osborne Reynolds, who talked about "sinuous motion" and wrote a paper using the most expressive phrase "écoulement tourbillonnant et tumultueux". This was abridged by one of his followers to "régime turbulent", hence the word turbulence.

Boussinesq made important contributions to all branches of mathematical physics, except that of electromagnetism. His work on hydraulics was considerable. He studied whirlpools, liquid waves, the flow of fluids, the mechanics of pulverulent masses, the resistance of a fluid against a solid body, and the cooling effect of a liquid flow. His contributions to the study of turbulence were praised by Saint Venant, and those on theory of elasticity by Love. Although he approached mathematics only in order to apply it practically, he still made important contributions. Notably, in 1880 he came upon nonanalytic integrals of hydrodynamic equations.