Identification of Stream Dispersion Coefficients by Adjoint Sensitivity Method

• Published in: Journal of hydraulic engineering (New York, N.Y.) Vol. 125; no. 7; pp. 714 - 724
• Main Authors: Piasecki, Michael, Katopodes, Nikolaos D
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.07.1999
• Subjects: Applied sciences; Bathymetry; Brackish; Buildings. Public works; Diffusion; Estuaries; Exact sciences and technology; Freshwater; Hydraulic constructions; Hydrodynamics; Optimization; River flow control. Flood control; Rivers; TECHNICAL PAPERS; Turbulence; Two dimensional; Velocity; ANW, USA, Potomac Estuary; Sensitivity analysis; Stream discharge; Estuaries; Equation; Adjoint method; Hydrodynamic dispersion; Two dimensional model; Concentration measurement; Parametric method; Non linear model; Variational calculus; Numerical simulation; Stream; Particle transport; Method study
• ISSN: 0733-9429; 1943-7900
• DOI: 10.1061/(ASCE)0733-9429(1999)125:7(714)

A numerical technique is presented for identification of spatially distributed dispersion coefficients for 2D mass transport in vertically mixed rivers and estuaries. The method is based on a nonlinear optimization procedure that minimizes the squared error between observed and computed concentration values. Gradient information is efficiently computed by the adjoint sensitivity method, so that the same effort is required regardless of the number of parameters involved. The method's limitations are presented, and the conditions of identifiability of the dispersion coefficients are investigated. Numerical tests on complex bathymetric configurations are presented to provide guidelines for the optimum location of monitoring stations. A large-scale application is presented corresponding to the upper Potomac estuary.