Piecewise-Linear Interface

Interface Capturing Schemes for Free-Surface Flows, Fig. 3 Piecewise linear interface calculation (PLIC) in two dimensions... 

The formation of a microemulsion from an array of microtubes has been studied experimentally and computationally by Kobayashi and co-workers [92,93). They used the commercial code CFD-ACE, which uses a piecewise linear interface construction (PLIC) method to determine the interface. They used quarter symmetry, as the channels were eDiptical in shape, but the simulations still required 7-14 days on a 2.5 GHz Pentium IV processor. The simulations captured the main features observed experimentally, including the change of regime from continuous outflow of oil if the channel was below a critical aspect ratio, to a stream of droplets above this threshold. The model was also used to predict the droplet size as a function of oil properties and generally agreed well with the experimental data. 

The evolution of the interface and advection of the phase-indicator function is accomplished by reconstructing the interface within each computational cell and computing the volume flux that occurs from each cell to its immediate neighbors under the prevaihng flow. The surface reconstruction problem [11] is one of finding an interface with the correct unit normal vector which divides the computational cell into two regions, each occupied by the respective fluid phase. One popular way to accomplish this is using the Piecewise Linear Interface Calculation or Con-... 

Piecewise Linear Interface Calculation (PLIC) in two dimensions. 

Figure 15.1 shows a schema comparing the real fluid configuration, where Figure 15.1c shows the simple line interface calculation (SLIC) VOF and Figure 15.Id the piecewise linear interface calculation (PLIC) VOF (the latter is also referred to as Youngs method). From these data it can be seen that, in the SLIC VOF method, the interfaces are implemented as segments parallel to the x or y axis. Although the SLIC method is advantageous in terms of simplicity and...

Figure 1S.1 Interface reconstructions of fluid shown by (a) actual configuration (b) volume fraction (c) representation with simple line interface calculation (SLIC) and (d) piecewise linear interface calculation (PLIC) [12].

Combination of the volumetric phase fraction of the dispersed phase with the interface normal then allows a Piecewise Linear Interface Reconstruction (PLIC) [24]. It allows a reconstruction of the phase geometry inside the computational cells... 

For an accurate calculation of the volume flux, the location of the interface is reconstructed with the piecewise linear interface calculation (PLIC) method from the/held [24]. 

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