Predicting velocity and turbulent kinetic energy inside an emergent Phragmites australis canopy with real morphology

Natural plants have different morphologies, which may impact the velocity and turbulence structures inside the canopy interior. Laboratory experiments investigated streamwise velocity and turbulent kinetic energy ( TKE ) profiles inside a Phragmites australis canopy with natural morphology. Inside the canopies, velocity and TKE adjusted both in the streamwise and vertical directions. An exponential-based velocity model for a canopy with vertically uniform frontal areas (e.g., a cylinder array) was modified to predict the longitudinal profile of depth-averaged velocity inside a canopy with vertically varying frontal areas (e.g., a P. australis canopy). Considering the influence of plant morphology, the vertical profiles of velocity and TKE at each streamwise position were predicted using the predicted depth-averaged velocity and the frontal area of the plants. The predicted velocity and TKE had good agreement with the measurements, suggesting that the present study provides a valid method to predict the velocity and TKE profiles inside canopies with natural morphology. Plants with a greater vertical variation in the frontal area have a more significant influence on predictions, and this influence should be included to avoid overestimating velocity and TKE .