1. Scientific Researcher, Hydraulics Laboratory, Dept. of Civil Engineering, Ghent Univ., Sint-Pietersnieuwstraat 41, B-9000 Gent, Belgium. E-mail: robert.banasiak@ugent.be
2. Professor, Hydraulics Laboratory, Dept. of Civil Engineering, Ghent Univ., Sint-Pietersnieuwstraat 41, B-9000 Gent, Belgium. E-mail: ronny.verhoeven@ugent.be