Identification of the friction coefficient in shallow-water flows using optimal control theory

This paper presents a numerical method to identify the friction coefficient in natural free surface flows, based on the optimal control theory. A Lagr angian operator is introduced whose partial derivatives provide state equat ions, adjoint equations and the optimality condition. A stable finite eleme nt method is used for space discretization, and a solution algorithm along with a continuation procedure is proposed and tested for steady and transie nt shallow-water hows. This algorithm seems robust and converges for realis tic initial trials as well as for a large number of parameters.