The United States Forest Service (USFS), an agency of the U.S. Department of Agriculture (USDA), manages nearly 200 million acres (800,000 square kilometers) of federally owned forests and grasslands. One hundred fifty-four national forests and twenty grasslands in 44 states and Puerto Rico fall under the Forest Service’s jurisdiction, and the USFS is charged with both protecting and managing these natural resources.
The Forest Service has long been a leader in the development of technologies that reduce the drift of agricultural pesticides, which are applied to reduce populations of invasive species. The USFS has developed computer models to calculate how aerially sprayed pesticides disperse, and recent developments have expanded these simulation capabilities to include the dispersion of pesticides applied through ground spraying.
When the Forest Service needed experimental data to help develop computer models for ground-based forest and range spraying, they turned to CPP. Our air quality experts built a 1:25 scale model of a generic spraying vehicle and tested it in the boundary layer wind tunnel. The tests were specifically designed to better understand the wake behind the kinds of vehicles typically used for ground spraying of pesticides.
Our engineers characterized the wake behind the sprayer by measuring velocities at various locations behind the vehicle and for a range of boom heights. Using automated precision instrumentation, we carefully measured both average and fluctuating velocity components in order to understand the mean flow and the turbulent nature of the wake. Our air quality team then delivered a virtual three-dimensional map of this wake to our clients at the Forest Service.
By turning to CPP, researchers at the U.S. Forest Service gained valuable experimental data that they can use to test and validate their computational models. These data help the Forest Service improve forest and range pesticide application and ensure that pesticides stay where they are needed without adversely affecting adjacent lands.