Inertial Migration of Cylindrical Particle in Stepped Channel—A Numerical Study

Abstract

AbstractInertial migration of solid rigid particle in fluid flow occurs by the virtue of pure mechanical forces and it can play a pivotal role in separation techniques. The present computational study tries to capture the inertial migration dynamics of single rigid neutrally buoyant cylindrical particle in fluid flow which is residing in a stepped (sudden contraction) channel by determining the equilibrium position and migration time. The immersed boundary method based on feedback forcing scheme is used to develop the numerical model. The particle performs both translation and rotation motion according to the fluid flow condition and is modelled as rigid immersed boundary and the governing fluid momentum, and continuity equations are discretized using finite volume method in a staggered grid system and solved using semi-implicit fractional step algorithm. The study is mainly performed for centre and off-centre initial positions and its influence on the equilibrium position and migration time. It is observed that the equilibrium position is dependent on the initial position of release of particle. As initial position shifts from centre of channel, the particle equilibrium position also shifts accordingly. Further, the effect of height and length of step (contraction portion) on lateral migration is explored. The equilibrium position is found to be shifting towards the upper wall with decrease in height of step. However, the change in height of step does not have any significant effect on migration time of particle. It is identified that the increase in length of step reduces the migration time of particle although the equilibrium position remains same.KeywordsEquilibrium positionFeedback forcingImmersed boundary methodInertial migrationMigration time