Pair of particle chain self-organization in a square channel flow of Giesekus viscoelastic fluid

Pair of particle chain self-organization in a square channel flow of Giesekus viscoelastic fluid is studied by the direct forcing/fictitious domain method. The effects of particle diameter, initial particle distance, shear-thinning (n), Weissenberg number (Wi), and Reynolds number (Re) are explored to analyze the mechanism of particle chain self-organization in Giesekus viscoelastic fluid. The results show that the small particle at the equilibrium position moves faster than the larger one and then catches up with it to form a particle chain, in which the large and small particles are located at the front and the end of the chain, respectively. The particle pair with the same diameter cannot form the chain in Giesekus viscoelastic fluid. In addition, the larger the diameter ratio and the initial particle distance, the larger the absolute value of the particle velocity difference, the earlier the particle chain is formed. The particle chain will be formed early with increasing n, Re, and Wi.