Three-dimensional volume-conserving immersed boundary model for two-phase fluid flows

We present a volume-preserving scheme for two-phase immiscible incompressible flows using an immersed boundary method (IBM) in a three-dimensional space. The two-phase IBM employs a mixture of Eulerian and Lagrangian variables, where the fluid interface is represented by discrete Lagrangian markers exerting surface tension forces to the Eulerian fluid domain and the markers are advected by the fluid velocity. The interactions between the Lagrangian markers and the fluid variables are linked by the discretized Dirac delta function. The present study extends the previous two-dimensional research (Li et al., Volume preserving immersed boundary methods for two-phase fluid flows, Int. J. Numer. Meth. Fluids 69 (2012) 842–858) to the three-dimensional space. The key idea of the proposed method is relocating surface points along the normal directions to conserve the total volume. We perform a number of numerical experiments to show the efficiency and accuracy of the proposed method.