Turbulent kinetic energy budgets in a model canopy: comparisons between LES and wind-tunnel experiments
A comparative study of turbulence in a wind-tunnel model canopy is performed, using Large eddy simulation (LES) and experimental data from PIV and hot-wire anemom¬etry measurements. The model canopy is composed of thin cylindrical stalks. In the LES, these are represented using a plant-scale approach, while the scale-dependent Lagrangian dynamic model is used as subgrid-scale model. LES predictions of turbulence statistics and energy spectra are found to be in good agreement with the experimental data. Turbulent kinetic energy (TKE) budgets from the LES simulation are analyzed to provide more infor¬mation absent in the measurements. Results conﬁrm that sloshing motions at the low levels of the canopy are mainly driven by pressure ﬂuctuations. A difference between the energy ﬂux obtained from the energy spectrum and the SGS dissipation rate is observed, consistent with a spectral bypass mechanism in which the real spectral ﬂux due to cascade is smaller than that implied by the energy-spectrum level, due to direct drain by the canopy.
Record created on 2008-02-15, modified on 2017-02-23