Laboratory studies on the response of fine sediment to wind

Min Su, Peng Yao, Zhengbing Wang, Yongping Chen, Changkuan Zhang, Marcel J.F. Stive

Thursday 2 july 2015

11:30 - 11:45h at Mississippi (level 1)

Themes: (T) Sediment management and morphodynamics, (ST) Sediment transport mechanisms and modelling

Parallel session: 11A. Sediment - Transport

To investigate the effects of wind on the suspension of fine sediment, we perform a series of laboratory experiments on a type of in-situ sediments, which was collected from a silty tidal flat of the Jiangsu coast in China. For testing the combined effects of wave and wind, paddle waves are generated with wind blowing on the water surface. Quasi-steady suspensions were obtained under a wide range of wind conditions. Analyses of the suspended sediment concentration reveal that the wind indeed influences the motion of fine sediment, especially under a stronger wind condition. Furthermore, detailed analyses of the velocity in terms of a phase-averaged velocity and turbulence reveal that the response of this sediment to the wind is mainly through suspended load. Turbulence momentum induced by the wind can transport vertically and lead to a longer time sediment suspension. The influence depth depends on the ratio between the wind-induced turbulence and the accompanied attenuation.