Abstract
Analysis of movie films of a field of barley, combined with observations of the motions of individual plants, show that single stalks oscillate at a well-defined natural frequency even when stimulated by turbulent winds. Treating single stalks as resonant cantilevers allows the use of standard engineering methods to determine their elastic properties. Armed with these values, the application of similarity analysis to the equation of motion of a single stalk leads to criteria for aeroelastic modelling of wheat plants in the wind tunnel. A representative value for the spacing of stalks in a small section of model wheat field was calculated by referring to published data on momentum absorption in a variety of real and model canopies. Preliminary measurements of first and second moments of velocity in the model appear to confirm the importance of including elastic properties in wind-tunnel simulations of airflow in flexible crops.
Similar content being viewed by others
References
Bisplinghoff, R. L., Ashley, H., and Halfman, R.L.: 1957, ‘Aeroelasticity’, Addison-Wesley Inc., Reading, Massachusetts.
Cionco, R. M.: 1972, ‘Intensity of Turbulence Within Canopies with Simple and Complex Roughness Elements’, Boundary-Layer Meteorol. 2, 453–465.
Denmead, O. T. and Bradley, E. F.: 1973, ‘Heat, Mass and Momentum Transfer in a Wheat Crop’, Paper presented to First Australasian Conference on Heat and Mass Transfer. Melb. Aust.
Fraser, D.: 1977, ‘An Optimised Mass Storage FFT’, Assoc. of Comp. Mach. Trans. on Math. Software (in press).
Grass, A. J.: 1971, ‘Structural Features of Turbulent Flow over Smooth and Rough Boundaries’, J. Fluid Mech. 50, 233–235.
Inoue, E.: 1955, ‘Studies of the Phenomena of Waving Plants (“HONAMI”) Caused by Wind. Part 1. Mechanism and Characteristics of Waving Plants Phenomena’, J. Agric. Met. (Japan) 11, 18–22.
Ito, S.: 1968, ‘Inner and Outer Flow Velocity Distributions Through Tall Simulated Vegetation’, Technical Report (CER67-68JEC61), Fluid Dynamics and Diffusion Laboratory, Colorado State University.
Kawatani, T. and Meroney, R. N.: 1970, ‘Turbulence and Wind Speed Characteristics within a Model Canopy Flow Field’, Agr. Meteorol. 7, 143–158.
Meroney, R. N.: 1968, ‘Characteristics of Wind in and above Model Forests’, J. Appl. Meteorol. 7, 780–788.
Mulhearn, P. J., Banks, H. J., Finnigan, J. J., and Annis, P. G.: 1976, ‘Wind Forces and their Influence on Gas Loss from Grain Storage Structures’, J. Stored Prod. Res. 12, 129–142.
Nakagawa, H. and Nezu, I.: 1977, ‘Prediction of the Contributions to the Reynolds Stress from Bursting Events in Open-Channel Flow’, J. Fluid Mech. 80, 99–128.
Schwerdfeger, P., Radok, U., Bennet, J., van Meurs, B., Piggin, I., Ussher, A., and Wu, A.: 1975, ‘The Physical Environment of Plants’, in L. P. Smith (ed.), Progress in Biometeorology—Division C, Progress in Plant Biometeorology, Swets and Zeitlinger, B. V., Amsterdam, pp 11–20.
Seginer, I.: 1974, ‘Aerodynamic Roughness of Vegetated Surfaces’, Boundary-Layer Meteorol. 5, 383–393.
Seginer, I., Mulhearn, P. J., Bradley, E. F., and Finnigan, J. J.: 1976 ‘Turbulent Flow in a Model Plant Canopy’, Boundary-Layer Meteorol. 10, 423–54.
Shaw, K. J., Silversides, R. H., and Thurtell, G. W.: 1974, ‘Some Observations of Turbulence and Turbulent Transport within and above Plant Canopies’, Boundary-Layer Meteorol. 5, 430–449.
Snyder, W. H.: 1972, ‘Similarity Criteria for the Application of Fluid Models to the Study of Air Pollution Meteorology’, Boundary-Layer Meteorol. 3, 113–134.
Thom, A. S.: 1971, ‘Momentum Absorption by Vegetation’, Q. J. Roy. Meteorol. Soc. 97, 414–428.
Tutu, N. K. and Chevray, R.: 1975, ‘Cross-Wire Anemometry in High Intensity Turbulence’, J. Fluid Mech. 71, 785–800.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Finnigan, J.J., Mulhearn, P.J. Modelling waving crops in a wind tunnel. Boundary-Layer Meteorol 14, 253–277 (1978). https://doi.org/10.1007/BF00122623
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00122623