AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Particle Removal from the Surfaces in Turbulent Flow: Effect of Large-Scale Surface Roughness
BABAK NASR, Jing Qian, Morgan Minyard, Andrea R. Ferro, Goodarz Ahmadi, Suresh Dhaniyala, Clarkson University
Abstract Number: 293 Working Group: Aerosol Physics
Abstract There are several factors that affect particle removal from surfaces by turbulent flow. Amongst these factors, surface roughness is the most dominant one. In most studies that have investigated the effect of surface roughness on particle removal, the length-scale of roughness was considered to be much smaller than the particles. For the case of small-scale roughness, particle removal rates were seen to be higher than that for the smooth surface condition. Often, however, real surfaces have roughness that may be comparable or much larger in size than particles. To understand the fate of particles on such surfaces, a new multi-scale surface roughness model is developed. In our new model, substrates with large-scale surface roughness are described as wavy surfaces. The relation between the important parameters of such a wavy surface, i.e. amplitude and wavelength and the critical velocity required to remove a particle from the surface was theoretically modeled. The analysis shows that the critical velocity of removal approaches that of smooth surfaces for large roughness scales, but at intermediate scales (comparably to particle sizes) the critical velocity increases significantly compared to smooth surface condition. In this presentation, the details of the theoretical model and main results from our study will be presented and implication for resuspension of micron-sized particles from real-substrates will be discussed. Approved for public release, distribution is unlimited.