ON RESUSPENSION OF SPHERICAL PARTICLES FROM ROUGH AND SMOOTH SURFACES BY A WALL-NORMAL VORTEXetc15 Tracking Number 196 Presentation: Session: Wall-bounded flows 6 Room: Room B Session start: 10:30 Fri 28 Aug 2015 Ron Shnapp ronshnapp@mail.tau.ac.il Affifliation: Tel Aviv University Alex Liberzon alex.liberzon@gmail.com Affifliation: Tel Aviv University Topics: - Transport and mixing, - Wall bounded flows Abstract: A three-dimensional particle tracking velocimetry (3D-PTV) method was applied to study in details the single-particle resuspension (lift-off) events of large spherical particles. In order to increase statistics, we have utilized a wall-normal, tornado-like vortex that lifted the particles from surfaces of different roughness. Analyzing the three-dimensional particle trajectories, velocities and accelerations before, during and after the resuspension events, the resuspension efficiency was obtained directly. The results show that the lift-off efficiency from the rough surface is significantly higher than from the smooth one. We suggest a simplified mechanistic model based on the mobility parameter that can predict this peculiar effect. This study can lead to improved modeling of resuspension rates from smooth and rough beds. |