1. DHI-NTU Centre and School of Civil and Environmental Engineering, Nanyang Technological Univ., Nanyang Ave., Singapore 639798 (corresponding author).
2. Assistant Professor, Dept. of Mechanical Engineering, National Univ. of Singapore, Singapore 117575.
3. Associate Professor, Nanyang Environment and Water Research Institute and Maritime Research Centre, Blk N1-B1a-03, 50 Nanyang Ave., Singapore 639798.