Aerodynamics of a portable wind erosion tunnel for measuringsoil erodibility by wind

Abstract

Portable wind erosion tunnels must satisfy several aerodynamic criteria to ensure that the flow within them acceptably reproduces the atmospheric flow causing natural wind erosion.We define these criteria and use them to assess the flow and turbulence in two alternativedesigns of portable wind erosion tunnel: the first has a working section with an approximatelytriangular, ‘tent-shaped’ cross section, while the second has a conventional, rectangularworking section. The measurements were made with Pitot-static tubes and X-configurationhot-wire anemometers, over stable (non-eroding) rough surfaces, mainly mowed grass ofheight 1 cm. We found that, with careful attention to flow conditioning elements such ashoneycombs and tripping fences, an acceptable flow can be achieved in the rectangulartunnel. The flow in the tent-shaped tunnel is less satisfactory, exhibiting departures fromthe logarithmic wind profile law which depend on the surface roughness. Show more