A boundary integral method for the simulation of the deformation of axisymmetric compound non-Newtonian drops suspended in a Newtonian fluid which is subjected to an axisymmetric flow eld is developed. The boundary integral formulation for Stokes flow is used and the non-Newtonian stress is treated as a source term. The latter yields an extra integral over the domain of the non-Newtonian material in the boundary integral formulation. By transforming the integral representation for the velocity to cylindrical coordinates we can reduce the dimension of the computational problem. Apart from a numerical validation of the method we present simulation results for a drop consisting of an Oldroyd-B fluid and a viscoelastic material. Moreover, we extend the method to compound drops, which are composed of a viscous inner core encapsulated by a viscoelastic material. The simulation results for these drops are consistent with theoretical results from the literature. Moreover, it is shown that the method can be used to identify the dominant breakup mechanism of compound drops and its relation to the specic non-Newtonian character of the drops.
|Place of Publication||Enschede|
|Number of pages||35|
|Publication status||Published - 1997|
|Name||Memorandum / University of Twente, Faculty of Applied Mathematics, ISSN 0921-1969|