Large eddy simulation of a vertical buoyant jet in a vegetated channel

摘要

Predicting the flow and dilution of a buoyant jet in vegetated regions is widely applied in ecology and engineering practices. Large eddy simulation is used to study a vertical buoyant jet that was injected into a cross flow with emergent rigid vegetation. This simulation successfully reproduces the jet behaviour and the spatiotemporal evolution of vortex structures of turbulent jet with vegetation. The time-averaged velocity and temperature field are compared with the experimental results. The similarities and differences between the tests with and without vegetation are also studied. The existence of vegetation diminishes the channel velocity, thereby significantly increasing the jet penetration height and dilution. Spectral analysis is used to investigate the lengths of the vortices corresponding to the dominant frequency at different locations in the flow field.