Impact of biomechanical properties on the deflection behavior of live flexible aquatic vegetations

In nature, the flexural rigidity of the flexible aquatic plant stem varies along its height, necessitating its inclusion in the analysis of deflection geometry. This study compares the deflection behavior of three species of flexible aquatic plants, Nymphaea caerulea, Nymphaea alba, and Trapa natans L., under various combinations of forces. An analytical model is developed to estimate the deflection behavior of flexible vegetation, incorporating flexural variation, and later, it is validated with experiments. The results show that hydrodynamic forces dominate over hydrostatic forces under various submergence ratios in the estimation of deflected shape. The deflected behavior also indicates that the effects of lift, elastic, and buoyancy forces need to be considered along with drag and friction forces while dealing with flow through the flexible aquatic vegetation. The proposed model shows satisfactory results in predicting the deflection shape with R2 and RMSE values of 0.86 and 0.21, respectively. Further, the models are assessed with machine learning to check the effect of flexural rigidity and to predict the deflected shape.