Note on estimating bed shear stress caused by breaking random waves

• Published in: Oceanologia Vol. 63; no. 3; pp. 385 - 390
• Main Authors: Myrhaug, Dag, Ong, Muk Chen
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2021; Elsevier
• Subjects: Bed shear stress; Breaking random waves; Individual waves; Joint distributions; Surf and swash zones; Surf similarity parameter; Wave height; Wave height; Joint distributions; Surf and swash zones; Surf similarity parameter; Individual waves; Bed shear stress; Breaking random waves
• ISSN: 0078-3234
• DOI: 10.1016/j.oceano.2021.03.004

•A simple analytical method to estimate bed shear stress for breaking random waves is presented.•Spilling and plunging breakers on slopes are presented.•Combines a bed shear stress formula for breaking regular waves with a joint distribution of surf similarity parameter and wave height.•Examples of results for typical realistic conditions are provided. This note presents a method of how the bed shear stress caused by breaking random waves on slopes can be estimated. This is obtained by adopting the Sumer et al. (2013) bed shear stress formula due to spilling and plunging breaking waves on hydraulically smooth slopes combined with the Myrhaug and Fouques (2012) joint distribution of surf similarity parameter and wave height for individual random waves in deep water. The conditional mean value of the maxima of mean bed shear stress during wave runup given wave height in deep water is provided including an example for spilling and plunging breaking random waves corresponding to typical field conditions. Another example compares the present results with one case from Thornton and Guza (1983) estimating the wave energy dissipation caused by bed shear stress beneath breaking random waves.