Variation of wave directional spread parameters along the Indian coast

Directional spreading of wave energy is popularly modeled with the help of the Cosine Power model and it mainly depends on the spreading parameter. This paper describes the variation of the spreading parameter estimated based on the wave data collected at four locations along the East as well as the West side of the Indian coast. The directional spreading parameter was correlated with other characteristic wave parameters, like non-linearity parameter, and directional width. Working empirical relationships between them have been established. The mean spreading angle was found to be slightly lower than the directional width with a correlation coefficient of 0.8. The maximum spreading parameter, s , underwent a sudden reduction in its value with the increase in the value of directional width. The average value of the maximum spreading parameter for the locations studied was found to be 23. The study shows that the spreading parameter can be related to significant wave height, mean period and water depth through the non-linearity parameter and can be estimated with an average correlation coefficient of 0.7 for the Indian coast and with higher correlation coefficient of 0.9 for the high waves ( H S > 1.5 m ) .