Abstract
Residual currents around submerged asymmetrical structures, known as BaNK blocks, are quantitatively estimated in wave fields. Komatsu et al. (2001) proposed 'BaNK system' in order to cope with beach erosion and shoaling of fairways. The system is a method to control sediment transport using residual currents which are produced by plural submerged asymmetrical structures in a wave field. In this study, three kinds of dimensionless parameters which are the Keulegan-Carpenter number, Reynolds number and structure height relative to water depth are regarded as main dimensionless parameters for producing residual currents. Velocity distributions around half cylinder type BaNK blocks are measured in various wave conditions and structure heights in a wave tank. As a result of this study, the relationships between vertical residual current distributions around asymmetrical structures and the dimensionless parameters are found. Furthermore some empirical formulas are established to calculate residual currents generated by the BaNK system in a wave field.
