Author(s): Timothy I. Marjoribanks; Richard J. Hardy; Stuart N. Lane; Daniel R. Parsons
Linked Author(s): Richard Hardy, Stuart N. Lane, Daniel Parsons
Keywords: Biomechanics; large eddy simulations; streams and rivers; vegetated flows; vortex dynamics
Abstract: In this paper, we present and apply a new three-dimensional model for the prediction of canopy-flow and turbulence dynamics in open-channel flow. The approach uses a dynamic immersed boundary technique that is coupled in a sequentially staggered manner to a large eddy simulation. Two different biomechanical models are developed depending on whether the vegetation is dominated by bending or tensile forces. For bending plants, a model structured on the Euler–Bernoulli beam equation has been developed, whilst for tensile plants, an N-pendula model has been developed. Validation against flume data shows good agreement and demonstrates that for a given stem density, the models are able to simulate the extraction of energy from the mean flow at the stem-scale which leads to the drag discontinuity and associated mixing layer.