A Comparison of Numerical Models with Experimental Data for Stem Waves along a Vertical Wall due to Monochromatic Waves

Abstract

Recently, vertical-type structures are frequently constructed in coastal area to protect ports and operation areas. When the waves propagate at oblique angles to the vertical-type structures, stem waves are generated along a structure due to the nonlinear interaction of incident and reflected waves. Thus, for the design of vertical structures the stem waves should be accurately evaluated using numerical models. In this study the performance of three nonlinear wave models based on different types of governing equations, REF/DIF 1, COULWAVE, and SWASH, was compared by using the measured data from laboratory experiment. The comparison was focused on accurate calculation of nonlinear effect. Overall performance of three wave models to generate the stem waves is compared and discussed. All the numerical models simulated fairly well the diffraction and reflection of waves for small amplitude waves. However, the model accuracy was somewhat degenerated as the wave amplitude becomes large. Among the three models, COULWAVE could not accurately reproduce the stem waves. The nonhydrostatic model, SWASH, gives the best results which agree with the experimental measurements.