Sensitivity analysis of numerical wave predictions models, considering wind and geometry effects in rectangular lakes

Abstract

Wave prediction is one of the most important issues in coastal and ocean engineering. This study investigates the wave regime in lakes under different lake geometric parameters and wind speeds and directions. For this purpose several SWAN simulations are carried out to study the wave regime considering different geometry and wind conditions. The model sensitivity to computational grid size is thoroughly investigated to apply the optimum grid size for accurate results in the shortest computation time. SWAN results are compared with different empirical wave prediction methods for different lake geometries and winds. CEM and Krylov methods show the most accurate predictions in shallow water, and SMB and Krylov in deep water. Finally the effects of different parameters like fetch, depth, bed slope, wind direction, and wind speed on prediction of wave are studied. Results show that the increase in fetch length increases the wave height. Wind speed and direction will affect the length for fully developed wave regime. Bed slope increases the water depth and consequently the wave height, and wave reaches its fully developed condition in longer distance. In a lake with 10m depth wave height has an increasing trend for about 85km before reaching fully developed situations.