Sensitivity computations using first and second orders perturbative methods for the advection-diffusion-reaction model of pollutant transport

Abstract

This work aims to apply the disturbance theory to accomplish sensitivity computations in problems of pollutant transported in liquid media modeled through the advection-diffusion-reaction equation. The numerical solution of the differential equation that describes the behavior of the system was found via the SUPG ("Streamline Unwinding Petrov Galerkin") finite element technique. Simulations were done for different Péclet numbers. Then, the adjoint equation of the advection-diffusion-reaction equation was derived for the one-dimensional case and the expression of the coefficient of sensitivity of a generic functional related to a generic parameter was obtained. The sensitivities of the mean and instantaneous pollutant rates were analyzed with relation to the following parameters: drag speed of the flowing current and Péclet number. Results of the sensitivity coefficient obtained with first and second order perturbation methodology satisfactorily matched the same values calculated by the direct method, that is, by means of the direct solution of the advection-diffusion-reaction equation by changing the values of input data parameters