Estimation of the transmission coefficients of wave height and period after smooth submerged breakwater using a non-hydrostatic wave model. (1st August 2016)

• Record Type: Journal Article
• Authors: Zhang, Na; Zhang, Qinghe; Zou, Guoliang; Jiang, Xuelian
• Is Part Of: Ocean engineering. Volume 122(2016)
• Page Start: 202
• Page End: 214
• Publication Date: 2016-08-01
• Subjects: Smooth submerged breakwater -- Non-hydrostatic wave model -- Wave transmission coefficients -- Mean wave period; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2016.06.037
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: In the present study, new empirical formulas of wave transmission coefficients, including K p for the mean wave period and K t for the significant wave height, defined as the ratios between the transmitted and incident values of a smooth submerged breakwater, are proposed based on results simulated using the SWASH non-hydrostatic wave model. According to the analysis of the numerical results, both K t and K p are less than 1.0, and the transmitted peak period is close to the incident peak period in most cases. The reduction of wave height is mainly caused by energy loss due to wave breaking, and the reduction of the mean period is mainly caused by the generation of high-frequency harmonics after the submerged breakwater. Moreover, both K t and K p have good linear correlations with the relative submergences, and K p has a good linear relationship with wave steepness. The relative crest width and slope have no significant effect on the transmission coefficient of the submerged breakwater compared with the effects of the relative submergences and wave steepness. Based on the factors mentioned above, new empirical formulas are formed. The coefficients of determination ( R C o r 2 ) of K t and K p between measurements and values calculated using the new empirical formulas are 0.90 and 0.95, respectively, representing an improvement over the models ofVan der Meer et al. (2003) and Carevic et al. (2013) . The sensitivities of K t and K p to the variables in the empirical formulas are also investigated. According to the sensitivity analysis, a simplified formula of K t is suggested based on the relative submergence and breaker parameter, and a simplified formula of K p is proposed based on the relative submergence and wave steepness. Highlights: Non-hydrostatic wave model is performed to investigate the transmission coefficients. New formula of wave transmission coefficients for mean wave period K p is proposed. The reduction of the mean period is mainly caused by high-frequency harmonics. K p has good linear correlation with the relative submergences and wave steepness. The new formula is able to account for 96% variability of K p for smooth breakwater.