1. Department of Ocean Engineering, Indian Institute of Technology Madras , Chennai-600036, India
2. Tropical Marine Science Institute, National University of Singapore , 14, Kent Ridge Road, Singapore 119223
3. Hydraulic Engineering Section, Institute for Geotechnics, Waste Management and Hydro Sciences, Department of Civil Engineering, Bergische University Wuppertal , Pauluskirchstr. 7, 42285 Wuppertal, Germany Fax: