Title: Design, construction and calibration of a portable boundary layer wind tunnel for field use Authors
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 13, 2010
Publication Date: October 1, 2010
Citation: Van Pelt, R.S., Zobeck, T.M., Baddock, M.C., Cox, J.J. 2010. Design, construction and calibration of a portable boundary layer wind tunnel for field use. Transactions of the ASABE. 53(5):1413-1422. Interpretive Summary: Due to the impossibility of controlling the wind during meteorological wind storms, researchers have built wind tunnels to control and study the physical forces that control the movement of soil particles by wind. A few of these wind tunnels have been designed so that they may be employed on natural field surfaces. These designs have varied widely and have often been too small to allow development of a representative boundary layer or too large to employ in any but the most open and flat locations. We designed, built, and tested a portable field wind tunnel using readily available components that develops a half meter deep boundary layer and yet can be towed behind a standard pickup truck. The design can be deployed and operated by two persons and has been successfully and satisfactorily field tested at 7 locations in 4 states.
Technical Abstract: Wind tunnels have been used for several decades to study wind erosion processes. Portable wind tunnels offer the advantage of testing natural surfaces in the field, but they must be carefully designed to insure that a logarithmic boundary layer is formed and that wind erosion processes may develop without interference from the tunnel structures. Although large portable tunnels often meet the aerodynamic criteria, their size and transportation requirements often limit the locations where they may be employed. We designed and built a self-contained portable wind tunnel that is easily transported on a tandem-axle trailer and pulled with a pickup truck. The wind tunnel uses a centrifugal blower, a flow conditioning section with optional abrader material feed, and a 1 m tall and 0.5 m wide working section that can vary in length from 2 m to 6 m. The maximum wind velocity attainable is 18.7 m/s although a mid-height centerline velocity of 12.6 m/s is normally used for field testing of natural surfaces. Based on measure wind velocity profiles in the tunnel working section, a conservative estimate of boundary layer depth within the working section is 0.5 m. This wind tunnel has been used to test rangeland and cropped surfaces in several locations and has provided reliable and useable soil erodibility and dust emission data.