Sediment transport capacity of tidal currents and waves

摘要

A lot of estuaries and coastal regions in China are covered with silts and muds, which are easily suspended and transported under the joint action of tidal currents and wind waves, Therefore, the study on the sediment transport capacity of both tidalcurrents and wind waves is of theoretical and practical significance. However, because of the extreme complexity of the problem, the studies in the past were limited to the empirical analyses, and the theoretical exposition was not given yet. In establishing most empirical formulas, the orbital velocity of waves was added to the velocity of the tidal currents in order to express the complex dynamic factors. As the two velocities belong to different categories, their superposition does not have theoretical basis. The empirical formulas proposed by different investigators can only be applied to a limit range in which the data were measured, and the common law of sediment transport capacity cannot be revealed by these formulas. According to the energy approach adopted by Dou Guoren in the study on the sediment transport capacity of rivers and based on the principle of superposition of energy, the wave energy dissipated in suspending sediments is added to that of tidal currents, and a law of sediment transport capacity under the action of both tidal currents and wind waves is deduced theoretically. Verification shows that the sediment transport capacity law obtained in this note is of universality and can be applied to various estuaries and coastal regions.