Using Stokes Cradle to Investigate Collisions Between 3 Wetted Particles

Understanding the mechanics of wetted particles has various applications, among them granulation, filtration, spray coating, and pneumatic support. Previous experimental and theoretical research includes two-particle collisions, both normal and oblique in nature. In this work, the scope has been extended to include normal, three-particle collisions. We use an apparatus called a “Stokes Cradle” which is similar to a Newton's Cradle, the common desktop toy where two motionless particles are impacted by an incoming third particle. The Newton's Cradle has been modified such that the two target particles are covered with a liquid coating or "wetted". The outcomes of the collisions can be divided into four categories depending on which particles are agglomerated versus separated. Thus far, the outcomes observed have included all three particles fully agglomerated, all three particles separated, and the two target particles agglomerated with the third incoming ball separated ("reverse" Newton's cradle). The mechanical interactions leading to each of these outcomes will be discussed.