Bottom shear stress and bed load sediment transport due to irregular wave motion

Waves in ocean are generally irregular and have a random shape with variation in orbital velocity, wave height and period. The accuracy of sediment transport model is the most important stage to model the coastal morphological change. In addition, the coastal morphological change model is more efficient to use the bottom shear stress calculation approach for practical purposes rather than a more complex approach to the modeling of two phases. In this paper, the calculation method of sediment transport based on the bottom shear stress purposed with data validation from the experimental results in the turbulent bottom boundary layer over rough bed under irregular waves. The new approach to estimate the bottom shear stress was based on combining velocity and acceleration terms as formulated [1] was modified to be proposed to calculate the bottom shear stress under irregular wave motion. Furthermore, a new approach of the bottom shear stress was applied to model the bed load sediment transport rate for irregular waves by using the experimental data as validated model. Measurement of water surface elevation and bed load sediment transport rate under irregular wave motion was carried out in wave flume tank generated by Jonswap spectrum in variation of wave height and period. Moreover, the new method gave the smallest the RMSE value indicating that the new method has the best agreement with the bottom shear stress and bed load sediment transport of experimental results.