Numerical Simulation of Bubble Rising in Viscoelastic Media by WC-SPH

In this study, the motion and deformation of a single bubble in initially quiescent viscoelastic fluid is investigated through a modified weakly compressible smoothed particle hydrodynamics (WC-SPH). It is considered that the base fluid obeys Oldroyd-B constitutive model. Indeed, the surface tension effects are simulated based on continuum surface force (CSF) method. First, the developed code is verified against available Newtonian and viscoelastic data and then, it is utilized to investigate the effect of different model parameters on bubble rising velocity and its shape. It is shown that the bubble trailing edge could form a cusp shape during its rise in viscoelastic fluids in some circumstances which is one of the fundamental aspects of bubble rising in viscoelastic media. Furthermore, the negative wake in the wake of the bubble is captured as reported in previous literatures. The excellent agreement between acquired results and previous published results proves that the developed WC-SPH algorithm is a good candidate for simulating unsteady multi-phase problems with large density (i.e. 1000) and viscosity (i.e. 100) ratios not only in Newtonian media but also in viscoelastic ones.