Numerical Modeling of Wind-Waves and Its Effect on Sediment Transport—An Investigation of Spectral Terms

Abstract

The interaction between wind waves and sediment movement at shores is a complex process, and its understanding is important. An accurate wave forecasting can result in better estimates of sediment movement along beaches. In addition, it will provide opportunities for improved planning and taking appropriate safety measures against the extreme events. A number of numerical models for wind-wave prediction are available which use inherent physics for wind-wave evolution. These models perform better for deep water predictions but still lack full understanding of balance of sources terms in finite water depth. An enhanced understanding of these terms will result in better estimation of sediment transport on beaches. The present study provides increased insight into the variation of two important source terms; non-linear wave-wave interactions and bottom friction which have significant effect on sediment transport. The non-linear wave-wave interactions have positive and negative signature and is the least understood term in wind-wave evolution. The bottom friction is always negative and withdraws energy from the spectrum. Thus, this study has provided better understanding of these two terms, and shows that together these affect the development of peak of the spectrum and hence wave energy. Consequently, because of their importance it will affect sediment balance at the shore. DESCRIPTION OF THE MODEL: The understanding of ocean wave dynamics plays an important role in understanding the effects of waves on the processes and structures affected by these; the examples include, design of on-shore and off-shore structures, on-shore and off-shore sediment transport (thus beach dynamics) and extreme events such as hurricanes, coastal flooding and others. Wind-wave modeling is an important component of such studies. It provides an excellent tool for hindcasting as well as predicting wave conditions as a future event in time and space. The suitable representation of physical processes responsible for wave growth and numerics of the model contribute towards obtaining better