Application of genetic algorithms to calibration and verification of QUAL2E

Göktaş, Recep Kaya
The objective of this study is to develop a calibration and verification tool for the QUAL2E Model by using Genetic Algorithms. In the developed optimization model, an objective function that is formulated on the basis of the sum-of-least squares approach aiming at minimizing the difference between the observed and simulated quantities was used. In order to perform simultaneous calibration and verification, verification of the calibrated results was treated as a constraint and inserted into the objective function as a penalty function. The performance of the optimization model was tested for different observation data qualities represented by the synthetic perfect and biased data sets. Although it was not possible to obtain the exact values of the kinetic coefficients for any of the tests performed, the coefficient estimates were successful in reflecting the water quality variable profiles in the river. The results of the tests showed that the performance of the optimization model is generally sensitive to the error in the observed data sets, to the number and location of sampling points, and to the objective function formulation. For the problems that involve multiple water quality variables, a weighting approach used in the objective function formulation resulted in better performances. The optimization model was also applied for a case study. For the same input data, calibration obtained with the genetic algorithm optimization ا simulation was better compared to the trial-and-error approach.


Elfarra, Monier A.; Akmandor, I. Sinan; Sezer Uzol, Nilay (2011-03-25)
The main purpose of this paper is to optimize winglet geometry by using CFD with Genetic Algorithm and study its effects on power production. For validation and as a baseline rotor, the NREL Phase VI wind turbine rotor blade is used. The Reynolds-Averaged Navier-Stokes equations are solved and different turbulence models including the Spalart-Allmaras, k-epsilon Launder-Sharma, k-epsilon Yang-Shih and SST k-omega models are used and tested. The results of the power curve and the pressure distribution at dif...
Investigation of algae distribution in Eymir Lake using site measurements and remotely sensed data
Elahdab, Tarek; Aksoy, Ayşegül; Department of Environmental Engineering (2006)
The aim of this study is to determine the distribution of Chla in Eymir Lake using remotely sensed data and in-situ data. The study was carried out in three phases; the first phase was taking ground real data from the lake for a 6-month period, secondly the remotely sensed satellite image was taken and analyzed, thirdly a correlation was obtained between the ground data and satellite image, and lastly mapping of the Chla in the lake was made. During the study also the change of the lake during the 6-month p...
Application of genetic algorithms for calibration and verification of QUAL2E model
Göktaş, Recep Kaya; Aksoy, Ayşegül (null; 2004-07-01)
Traditional trial-and-error methods make the calibration and verification of a model considerably time consuming. In addition, it is doubtful whether the best results will be achieved. However, by use of optimization techniques in calibration and verification, the best kinetic parameter estimates can be obtained in a shorter time period. In this study, a genetic algorithm (GA) is used to determine the reaeration coefficients for QUAL2E. An objective function, defined by sum-of-least-squares, is used in orde...
Validation of Parallel WRF Downscaling Methodology using OpenFOAM
Leblebici, Engin; Tuncer, İsmail Hakkı (2017-06-26)
The main objective of this study is to obtain real-time atmospheric flow solutions using open source CFD solver OpenFOAM coupled with Numerical Weather Prediction (NWP) model; Weather Research Forecast (WRF). NWP can take moist convection, land surface parameterization, atmospheric boundary layer physics into account, but wind flow features finer than 1 km aren't captured by the turbulence physics of such models. CFD simulations, however, have proved to be useful at capturing the detail...
Extending Voronoi-diagram based modeling of oil slick spreading to surface tension-viscous spreading regime
Durgut, İsmail; Reed, Mark (Elsevier BV, 2020-11-01)
An earlier paper demonstrated a methodology for modeling the spreading process with a Gaussian random walk procedure, but was limited to the gravity-viscous spreading regime. Here we extend the methodology of re-presenting spread and transport of oil slicks on calm sea surface by updated Voronoi diagrams to account for the surface tension-viscous spreading regime as well. We have utilized the analogy between diffusion and spreading processes by defining a step length for the particle-based random walk schem...
Citation Formats
R. K. Göktaş, “Application of genetic algorithms to calibration and verification of QUAL2E,” M.S. - Master of Science, Middle East Technical University, 2004.