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United States Department of Agriculture

Agricultural Research Service

Title: Relationship of Density Index to Velocity Profiles of An 8-Row Plastic-Pipe Windbarrier.

Authors
item Bilbro Jr, James
item Stout, John
item Fryrear, Donald

Submitted to: Proceedings of the International Symposium on Wind Erosion
Publication Type: Proceedings
Publication Acceptance Date: June 4, 1997
Publication Date: N/A

Interpretive Summary: Wind erosion causes dust particles to become airborne and transported for long distances. These dust particles cause many problems, including pollution of the atmosphere, visibility reduction, and health maladies. Windbarriers reduce wind velocities, and consequently they reduce wind erosion problems. Research was conducted to determine the effectiveness of a plastic-pipe windbarrier in reducing wind velocities. The results were mathematically described in an equation that can be useful in making computer programs that can predict wind erosion reductions by windbarriers of various kinds.

Technical Abstract: Wind erosion is a naturally occurring process that degrades soils, pollutes the environment, and increases health problems. Windbarriers can reduce wind erosion significantly. Therefore, we are developing relationships between density indexes (DI) and downwind velocity patterns for artificial and vegetative windbarriers for modeling purposes. This report presents results from an 8-row, 1-m high, plastic-pipe (PP) windbarriers. Wind velocity data were obtained from the windbarrier for four different per-row optical densities: 12.5%, 25%, 50%, and 75%. The density indexes for these respective per-row optical densities are 100, 200, 400, and 600 (e.g. 12.5 X 8 = 100). The reference anemometer was placed 43 h upwind (h = one meter, the height of the barrier); and anemometers were light-weight, had a starting speed of about 0.3 m/s, and were 20 cm tall. Velocity data were accumulated for each of the four optical-density windbarriers. Through curve-fitting analyses the relationship of density index and "percent of upwind velocity" (open-field) was established.

Last Modified: 12/26/2014
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