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Canopy Morphology in CFD Simulations. Cian Desmond, Simon Watson, Sandrine Auburn. Production of kinetic energy. Resisting force. Wind. Dissipation of kinetic energy. LEAF AREA DENSITY. Current Method. A(z) =. Total one sided Leaf area (m 2 ). Total volume (m 3 ). δ. z.
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Canopy Morphology in CFD Simulations Cian Desmond, Simon Watson, Sandrine Auburn
Production of kinetic energy Resisting force Wind Dissipation of kinetic energy LEAF AREA DENSITY Current Method
A(z) = Total one sided Leaf area (m2) Total volume (m3) δ z Leaf Area Density
IS THIS BENEFICIAL? LEAF AREA DENSITY Canopy Structure
Validation Data
Available data: • Mean U, V, W • Variance u’, v’, w’ • Lucien Malavard wind tunnel • 5m x 5m x 12m • U∞ = 4.5 m/s • Stereo – PIV measurments • Two 2048 x 2048 pixel cameras Validation Data
a(z) = Source + Sink Terms Model Trees
ANSYS CFX 14.0 • RANS Simulation • SST Turbulence Model • Cells: 6,721,511 • 10 x cells beneath canopy CFD
Velocity Correlation 10 x LAD Profile Full LAD Profile Full LAD Profile z z Mean LAD Correlation coefficient LAD LAD CHEAP Mean LAD Full LAD Profile z Mean LAD LAD EXPENSIVE Morphology
Hc Inlet Hc 2 Hc 3 Hc 4Hc 5Hc 6Hc 7 Hc 8Hc 9Hc 10Hc 11Hc 12 Hc Inlet Inlet Velocity (m/s) TKE (m2/s2) CFD Wind tunnel CFD V Wind Tunnel
TKE 4 Hc 12 Hc 40 Hc Ambient turbulence + 25% 9 Hc 4 Hc Hc Extent of wake
OS maps can be misleading • Seasonal, annual and forest management variations • Correct LAD profile more important than geometry • Cheap, effective tools exist to accurately measure LAD • No significant increase in computation time by ddincluding full LAD profile • Tuning of LAD to match observations can cause issues • – Stability? Conclusions
Sirta site Percentage occurance Wind speed at 100m - Unstable - Neutral - Stable Results