Abstract
Wind velocity statistics from several points within a regular but sparse array of clumped corn plants are analyzed, with each clump consisting of 12 plants, having a mean height of 1.6 m and a collective leaf area of about 2.75 m2 and occupying approximately 0.8 m2 of ground area. The clumps defined the (484) nodes of a square lattice, with side length of 5.6 m, and this lattice covered an area of 120 m × 120 m within an otherwise uniform corn field. Forty-eight half-hour records of daytime mean “cup” wind speeds and turbulent kinetic energies k, from several points in the canopy, are displayed against a “reduced” mean wind direction that exploits the symmetries of the canopy. These data conform well with the corresponding fields from a three-dimensional, steady-state wind model (with eddy viscosity ∝ λk1/2, where λ is the length scale). Both the observations and the model confirm the importance of a set of special wind directions, some of which place a given point P in the shelter of a nearby clump (“blockage”) and others of which place P in a “corridor.”
Corresponding author address: Andree Tuzet, Institut National de la Recherche Agronomique, E.G.C., 78850 Thiverval-Grignon, France. tuzet@bcgn.grignon.inra.fr
