Differentialgleichungen ( DGL )

Adhémar Jean Claude Barré de Saint-Venant
23 August 1797 - 6 Januar 1886

 I   y_t = -v_xy - vy_x    

 II  v_t = -vv_x - gy_x - E

III   c = √¯gy            

http://www-groups.dcs.st-andrews.ac.uk/~history/Mathematicians/Saint-Venant.html