CENTER FOR COMPUTATIONAL MATHEMATICS COLLOQUIUM

                  UNIVERSITY OF COLORADO AT DENVER



TITLE:   Identification of the friction coefficient in shallow-water flows 
         using the finite elements and adjoint methods
 

SPEAKER: Azzeddine Soulaimani, Ecole de technologie superieure, 
         Universite du Quebec, Montreal, Canada
         
DATE:    Monday, March 9, 1998  


PLACE:   Mathematics Conference Room 626 
         UCD Building, 1250 14th St., Denver


TIME:    noon (Refreshments served at 11:45 am) 



ABSTRACT

In this talk we present a numerical method to identify the friction 
coefficient which governs natural free surface flows. This friction 
coefficient reflects the very nature of the waterway bed. It is 
variable in space and its effect is dominant in natural shallow-water 
flows, however, only approximate values can be a priori prescribed. A 
calibration procedure is generaly necessary in practical applications.  
The optimal control theory (adjoint method) is applied for identifying 
this uncertain parameter.
A Lagrangian operator, which partial derivatives provide respectively 
the state equations, the adjoint equations and the optimality condition, 
is introduced. A stable finite element method is used for space 
discretization.  
Two solution algorithms are proposed and tested on some steady and 
unsteady benchmark flows. Also, a solution strategy is proposed to 
identify large numbers of parameters.