Particle Spinning Motion during Saltating Process

Impact of continuous particle size distribution width and particle sphericity on minimum pickup velocity in gas–solid pneumatic conveying

“…Notably, differences in particle sphericity (φ) lead to variations in (i) particle rotation and (ii) particle lift (Hölzer and Sommerfeld, 2009;Zastawny et al, 2012), both of which impact U pu values. Correspondingly, the extent of nonmonotonic behavior gives an indication of the impact of particle shape, because the higher representation of the larger particle sizes in the wider PSDs enhances the particle rotation and lift effects (Lee and Hsu, 1996). The U pu values for each material are normalized with respect to the U pu of the monodisperse system (σ/d sm ¼ 3%) to facilitate a more direct contrast, as shown in the normalized plot of U pu values in Fig.…”

“…PSDs (σ/d sm 4 30%) of non-spherical (φ o1) particles, because the air supplied has to overcome the increased drag due to more extensive rotation associated with the larger particles (Lee and Hsu, 1996), the U pu value is correspondingly more amplified.…”

“…Similar to the effect of particle rotation, some of the air supplied has to be expended in overcoming the particle lift of the non-spherical particle in the direction perpendicular to fluid flow. As a result, due to the enhanced effect of particle lift associated with the larger particles (Lee and Hsu, 1996) in wider PSDs (σ/d sm 4 30%), the U pu value of non-spherical particles (φo1) increases relative to that of spherical ones (φ ¼1).…”

A method for characterising solids translational and rotational motions using Multiple-Positron Emission Particle Tracking (Multiple-PEPT)

“…Most of the previous rotation studies focused on solid rotation by means of high-speed photography (Tsuji et al, 1985;White and Schulz, 1977;White, 1982;Lee and Hsu, 1996) using a stroboscope. The solids used were marked with some special lines or spots on their surfaces in advance, so rotation speeds could be recognized easily.…”

Lagrangian Modelling of Saltating Sediment Transport: A Review

“…However, it soon turned out that it was only possible to calculate the several trajectories of particles, which was insufficient for calculation of the bedload rate, so the goal was transformed into improving the models, such that they might be used further when the development of computers allowed for their employment. The focus was on better description of the shape of a single trajectory through more accurate assessment of the impact of individual processes such as: collisions between particles (Sørensen and McEwan 1996;Schmeeckle et al 2001;Lee et al 2002;Yeganeh-Bakhtiary et al 2009;Bialik 2010Bialik , 2011aMoreno and Bombardelli 2012), particles' collisions with the channel bottom (Sekine and Kikkawa 1992;Niño and Garcia 1994;Lukerchenko et al 2006;Bialik 2011b, Kharlamova andVlasak 2015), taking into account the three-dimensional nature of the particles' motion (Lee et al 2006;Lukerchenko et al 2009a;Bialik et al 2012) or a better approximation of the different forces acting on the flowing particles, such as: Basset force (Bombardelli et al 2008;Lukerchenko et al 2012), lift force (Lee and Hsu 1996;Zou et al 2007;Lukerchenko et al 2008) and drifting force (Lee 1987;Lee and Wiesler 1987;Czernuszenko 1998) due to turbulent diffusion, which, with some exceptions (Rowiński and Lee 1993;Rowiński 1995), has usually been neglected in the Lagrangian models of sediment transport. It should be noted that all of these models mostly skip the idea of their creation, namely their use for the evaluation of the phenomena associated with the movement of particles near the bed region.…”