Application of a Surface Tension Method for VOF using a Marching-Cube Isosurface Construction Algorithm to Complex Hydrodynamic Flows
Résumé
The accurate modeling of surface tension is an important prerequisite to correctly simulate the phenomena that take place in smaller scales. However, modeling surface tension for complex hydrodynamic flows, such as marine applications, poses several difficulties. More specifically the method has to deliver accurate curvature results for absurdly changing topological features of the free surface. As a result, the topological features of the free surface have to be dynamically recovered during the calculation. In this work, we present a surface tension (ST) method implemented in the VOF-RANS flow solver ISIS-CFD [1], that has the above features and present preliminary results obtained for a flat inclined plane cutting the free-surface in an asymmetric flow. In order to capture the geometry of free-surface, the method uses a marching cube algorithm (see for example [2]). The algorithm dynamically generates the grid of the volume fraction isosurface representing the free surface. The curvature is calculated by the generated grid, using a high-order differencing method based on least squares. The results obtained for the test case studied, demonstrate that the method can be used in practical cases to directly visualize complex three dimensional flow regimes and investigate the surface tension effects for smaller scales. For example, the figure below shows the unstructured surface grid generated for the ventilating air vortex emanating near the plate's (transparent plane) submerged leading edge corner and a detail of the free surface roll-up.
REFERENCES
[1] P. Queutey and M. Visonneau, “An interface capturing method for free-surface hydrodynamic
flows”, Computers and Fluids, Vol. 36, pp. 1481−1510, (2007).
[2] T.S. Newman, H. Yi, “A survey of the marching cubes algorithm”, Computers and Graphics,
Vol. 30, pp. 854–879, (2006).
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