American Association for Aerosol Research - Abstract Submission

AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA

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Aggregation during the Crossover from Ballistic to Diffusive Motion

William Heinson, Chris Sorensen, AMIT CHAKRABARTI, Kansas State University

     Abstract Number: 332
     Working Group: Aerosol Physics

Abstract
We investigate, through simulation, a system of aggregating particles in the free molecular regime that undergoes a crossover from ballistic to diffusive motion. As the aggregates grow, the aggregate mean free path becomes smaller and the motion between collisions becomes more diffusive. From growth kinetics we find that when the ratio of the mean free path to the aggregate nearest neighbor separation reaches of the order of unity , a crossover to diffusive motion occurs. This ratio, called the nearest neighbor Knudsen number, becomes an important parameter in understanding aerosol aggregation in the free molecular regime.