A modified breaker index formula for depth-induced wave breaking in spectral wave models. (15th November 2022)

• Record Type: Journal Article
• Authors: Chen, Zereng; Zhang, Qinghe; Wu, Yongsheng; Ji, Chao
• Is Part Of: Ocean engineering. Volume 264(2022)
• Publication Date: 2022-11-15
• Subjects: SWAN -- Coastal water -- Breaker index -- Mild beach slopes; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2022.112527
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: The breaker index, defined as the ratio of wave height to local water depth for incipient breaking, is a key parameter in contemporary spectral wave models. In the present study, we modified the breaker index of Goda's formula using the SWAN model (Simulating WAves Nearshore). We suggested that the breaker index is a function of the deep-water wave steepness, bottom slope and relative water depth. The formula is evaluated against observational data, and the evaluation indicates that the modeled wave heights using the formula are significantly improved, especially for cases over mild and flat slopes. The formula is further evaluated through comparisons with published formulas and the improved formula overall shows better performance. Highlights: A new breaker index formula used in spectral wave model is presented by modification of Goda (2010). It solves the uncertainty of the empirical coefficient of Goda's formula through considering the deep-water wave steepness. The updated breaker index can be used in a very large range of beach slopes for SWAN model simulation. Experimental wave height data over 1:100 to 1:300 beach slopes are provided.