PART VII: APPLICATIONS OF THE NUMERICAL MODEL 



442. The numerical model developed in this study and its calibration 

 are described in Part VI. The model was calibrated by comparison to the large 

 data base of LWT experiment results obtained by using constant waves and water 

 level. In this chapter, sensitivity analysis is conducted with respect to a 

 number of model parameters to evaluate their influence on the calculated 

 results. Predictions of the model are examined for a variety of hypothetical 

 cases, including varying wave and water level conditions. Consideration is 

 also given to simulation of multiple bars. The model is then put to the 

 severe test of reproducing beach profile change, in particular, bar movement 

 in the field. Example applications of the model are made to investigate the 

 effect of a vertical seawall on beach profile development, as well as initial 

 adjustment of beach fill. Comparison with an existing model, the Kriebel 

 model (Kriebel 1982), is made for a number of hypothetical conditions to 

 evaluate the importance of bar formation on beach erosion. Finally, model 

 simulations are made to qualitatively reproduce onshore sand transport and 

 berm buildup. 



Sensitivity Analysis of Model Parameters 



443. A sensitivity analysis was performed to quantify the influence of 

 various model parameters and empirical coefficients on simulation results. 

 Sensitivity analysis gives valuable information about the physical implica- 

 tions of the model parameters and their relative effects on the result. It is 

 important to explore the predictions of the model beyond the range in which it 

 was calibrated to determine if expected and intuitively reasonable trends are 

 obtained. In the following, the influence of principal model parameters on 

 beach evolution is discussed mainly by reference to bar properties. To this 

 end, the change in shape and size of the bar is investigated for a specific 

 case (Case 401) under perturbations of optimal values of model parameters as 

 determined by the calibration. 



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