직립구조물 전면의 연파 특성에 관한 연구

Abstract

In this study, precisely-controlled laboratory experiments and numerical simulations were conducted on monochromatic and random waves and the various differences in stem wave characteristics depending on wave properties examined. The numerical simulations were conducted using REF/DIF parabolic approximation equations and the Simulating WAves till SHore (SWASH) non-hydrostatic numerical model. The results obtained verified that increases in the incident angle and nonlinearity of incident waves result in the appearance of stem waves and increasingly wider stem widths. The normalized wave height along the structure showed similar patterns for both monochromatic and random waves, whereas large differences were observed in the distribution patterns of the wave height in the direction normal to the structure. The experimental results were consistent with the theoretical solution for wave nonlinearity; however, substantial discrepancies were observed as the wave nonlinearity increased. The experimental results for the random waves were in good agreement with the theoretical solution when the nonlinearity was weak, with increasing discrepancy dependent on the level of nonlinearity—possibly because the theoretical solution did not account for wave nonlinearity. The results from the two numerical models were in fairly good agreement with the results obtained in the laboratory experiments. However, the SWASH model outperformed the REF/DIF model as the nonlinearity of the incident waves increased. In particular, stem wave generation characteristics under random wave conditions were observed only with the SWASH model. The SWASH model was able to reproduce the effect of nonlinearity impeded by the interactions between the individual wave components of random waves, whereas the REF/DIF model could not. The data obtained from the laboratory experiments will be useful for checking the accuracy of wave propagation models.