A “test of concept” comparison of aerodynamic and mechanical resuspension mechanisms for particles deposited on field rye grass (Secale cercele). Part 1. Relative particle flux rates

Resuspension of uniform latex micro spheres deposited on a single seed pod of field rye grass stalk and head was investigated experimentally in a wind tunnel. The experiment was designed to distinguish aerodynamic (viscous and turbulent) mechanisms from mechanical resuspension resulting from the oscillatory impact of the grass hitting a stationary object. The experiment was run for deposited spherical latex particles with diameters from 2 to 10 μm. Wind tunnel tests were run for wind speeds from 2 to 18.5 m s−1 and a turbulence intensity (root-mean-square fluctuation wind speed/mean wind speed) of 0.1. Our experiments showed the following for our test of concept experiment: • Resuspension particle flux increases when mechanical impacts occur.• Mechanical resuspension dominated for 2 μm particles over purely aerodynamic resuspension, but for larger particles aerodynamic mechanisms were roughly equally effective in resuspending particles.