Comparison of wave refraction and diffraction models

Six numerical models: (1)RCPWAVE, (2)ReflDif-1, (3)RDE, (4)PBCG, (5)PMH, an d (6)MIKE 21's EMS module, were examined for their performance on the simul ation of water wave shoaling, refraction, and diffraction. Experimental dat a for waves traveling across an elliptic shoal were used as a standard for comparison. Although the last four models (i.e., elliptic or hyperbolic mod el) are capable of simulating strong wave diffraction, reflection, and reso nance, those capabilities were not compared because RCPWAVE:, Ref/Dif-1, an d the physical model experiment are only capable of simulating water wave s hoaling, refraction, and weak diffraction. The Ref/Dif-1 had excellent accu racy in the prediction of wave height; the predicted wave direction, howeve r, was not good. The RCPWAVE had accuracy problems in both wave height and direction. The next three models (RDE, PBCG, and PMH) all performed very we ll on the simulation of wave shoaling, refraction, and diffraction, and the y practically provided the same results for the case study presented. The E MS module for Mike 21 was slightly different than the previous three. Regar ding the simulation of the passing-through boundary, the PMH model was bett er because of the nearly exact solution for this boundary. The MIKE 21's EM S module had a faster computing pace, but no output for wave directions and was incapable of including tidal current effects were the major drawbacks.