Experimental study of the wave-induced current for emergent rigid vegetation under regular wave conditions

To understand the variation of the wave-induced current for emergent rigid vegetation, a series of laboratory experiments were conducted in a wave flume with two water depths, a variety of regular wave conditions, and two emergent plants modes. Based on the hypothesis testing, the predicting models for the canopy-drag length and the characteristic vegetation parameters were established respectively. The results showed that the current is predominantly induced by the root when the stem density was 60 plants/m². Based on this observation, a model for predicting the maximum temporal-averaged flow for emergent vegetation was proposed by the extension of the existing model derived from submerged vegetation. The stem can reduce the root-mean-square of the mean current, the relative reduction constant at and above the root was a parabolic function of Ursell number. In the distribution of cluster roots, the stem had a stabilizing influence on the vertical velocity structure, especially at the normalized vertical position corresponding to the maximum of the temporal-averaged flow velocity.