Microparticle detachment from surfaces exposed to turbulent air flow: microparticle motion after detachment

Effects of temporal flow acceleration on the detachment of microparticles from surfaces

“…The present study relates directly to three previous publications of the authors (Ibrahim et al, 2003a;Ibrahim, Dunn, & Brach, 2003b;Ibrahim, Dunn, & Brach, 2004). In those studies, the effects of a number of variables on microparticle incipient motion (detachment) were presented and the motion of the microparticles along the surface following detachment was studied.…”

“…This fraction is defined as n * (t) = 1 − [n(t)/n(0)], where n(t) is the number of non-detached microspheres on the surface at time t. The free-stream velocity at which n * (t) equals 0.5 is defined as the free-stream velocity for detachment, U th,∞ . The uncertainty in U th,∞ , under controlled conditions was approximately 15% (Ibrahim et al, 2003b).…”

“…Variables investigated included microparticle shape, density and size, particle residence time on the surface, particle deposition density, particle-surface adhesion energy, fluid relative humidity, fluid final free-stream velocity, fluid final Reynolds number, and slower fluid temporal accelerations. In Ibrahim et al (2003b), it was reported that relatively slow temporal accelerations (from 0.01 to 0.34 m/s 2 ) had little effect on microparticle detachment.…”

Source term models for fine particle resuspension from indoor surfaces

“…Resuspension can be characterized in terms of either the free stream velocity or the friction velocity [29]. Using the friction velocity is beneficial, because it allows for a comparison between experiments to be made at different flow configurations [30]. The meteorological wind velocity can be converted to friction velocity via a semi-log relationship.…”

Transport and modification of glaciovolcanic glass from source to sink on Mars

“…This paradoxal aspect of initiating sand mobility has been left partly unresolved by early wind tunnel studies as their set-ups have been ineffective for observing the first moments of particle detachment. The first type and moment of grain detachment has been frequently observed to have a rolling/rocking component, which results from the vertical flow gradient across the height (diameter) of a single sand grain (Reeks & Hall, 2001;Ibrahim et al, 2004Ibrahim et al, , 2008. Different types of wind tunnel studies were therefore performed by de Vet et al (2014b) using a hypobaric wind tunnel ( (Sullivan et al, 2005;de Vet et al, 2014b).…”