pps proceeding
Symposium: S03 - Rheology and Process Simulation Oral Presentation
A New Implementation of the Surface Tension Force to Reduce the Spurious Currents in Two-Phase Flow
Mostafaiyan Mehdi (1)*, Wießner Sven (1), Heinrich Gert (1)
(1) Leibniz Institute for Polymer Research Dresden - Sachsen - Germany
Spurious current, which can be defined as parasite-like velocity vectors and pressure jumps in the vicinity of the interface in two-phase flow system, is an unreal phenomenon and exist due to the flow field calculation errors in different numerical methods. Discontinuity of density and viscosity in the interface area, as well as inaccurate calculation of the interface curvature and normal vectors, are the parameters which are considered to be the source of the calculation errors and the spurious currents, consequently. The spurious currents can affect the numerical prediction of the second phase deformation, especially for the cases the capillary number is small (Ca<1.0).
In this research, a coupled computer code for flow field calculation is developed using Galerkin finite element method. Also, some temporary elements are defined in the vicinity of the interface and a moving least square technique is used to obtain a more accurate flow filed parameters in the interface area, without introducing new nodes or new DOFs (degree of freedom). Surface tension force is implemented in the solution using a pressure boundary condition on the temporary elements, which one of their edges lays on the interface.
It is shown that, using this technique, the fluctuation of the pressure as well as the magnitude of the parasite-like velocity vectors in the interface area will be reduced satisfactorily.