In Interwar France, Henri Villat became the true leader of theoretical
researches on fluid mechanics. Most of his original work was done before the
First World War; it was highly theoretical and its applicability was
questioned. After having organized the first post-WWI International Congress of
Mathematicians in 1920, Villat became the editor of the famous Journal de
math\'ematiques pure et appliqu\'es and the director of the influential book
series "M\'emorial des sciences math\'ematiques." From 1929 on, he held the
fluid mechanics chair established by the Air Ministry at the Sorbonne in Paris
and was heading the government's critical effort invested in fluid mechanics.
However, while both his wake theory and his turbulence theory seemingly had
little success outside France or in the aeronautical industry (except in the
eyes of his students), applied mathematics was despised by the loud generation
of Bourbaki mathematicians coming of age in the mid 1930s. How are we to
understand the contrasted assessments one can make of Villat's place in the
history of fluid mechanics
