Wave-current interaction during Hudhud cyclone in the Bay of Bengal

Abstract

The present work describes the interaction between waves and currents utilizing a coupled ADCIRC+SWAN model for the very severe cyclonic storm Hudhud, which made landfall at Visakhapatnam on the east coast of India in October 2014. Model-computed wave and surge heights were validated with measurements near the landfall point. The Holland model reproduced the maximum wind speed of ≈ 54ms-1 with the minimum pressure of 950hPa. The modelled maximum surge of 1.2m matches with the maximum surge of 1.4m measured off Visakhapatnam. The two-way coupling with SWAN showed that waves contributed ≈ 0.25m to the total water level during the Hudhud event. At the landfall point near Visakhapatnam, the East India Coastal Current speed increased from 0.5 to 1.8ms-1 for a short duration ( ≈ 6h) with net flow towards the south, and thereafter reversed towards the north. An increase of ≈ 0.2m in Hs was observed with the inclusion of model currents. It was also observed that when waves travelled perpendicular to the coast after crossing the shelf area, with current towards the southwest, wave heights were reduced due to wave-current interaction; however, an increase in wave height was observed on the left side of the track, when waves and currents opposed each other.