AN EXPERIMENTAL INVESTIGATION ON INFLUENCE OF AIR VOID IN SAND DUNE SEDIMENT TRANSPORT DUE TO OVERWASH

摘要

Laboratory experiments were conducted to investigate the mechanisms and parameters involved in dune sediment transport due to overwash. A total of 16 experimental runs have been conducted comprising of three types of sand on two different slopes for three bore condition. In each experiment, initial dune condition was set as: (i) dry and, (ii) wet. Influential parameters and mechanisms were identified to explain the sediment transport behavior. Fine sand in wet condition exhibited highest erosion resistance. Coarse sand is dominated by porosity and the shorter time ratio for in/exfiltration. Angle of repose was considered to be a key parameter to distinguish sediment transport between dry and wet condition. These parameters are expected to be incorporated in theoretical analysis as well as numerical modeling.