Proper orthogonal decomposition of flow-field in non-stationary geometry

The current paper outlines a proper orthogonal decomposition (POD) methodology for a flow field in a domain with moving boundaries. In the standard POD approach the properties of the region of the domain, which alternatingly occupied by fluid and solid, are not defined. Here, prior to the decomposition, the domain with moving or deforming boundaries is mapped to a stationary domain using volume preserving mapping. This mapping was created by combining a transfinite interpolation and volume adjustment algorithm. The algorithm is based on an iterative solution of the Laplace equation with respect to the displacement potential of the grid points. Finally the method is demonstrated on CFD results of pitching and plunging ellipse in still fluid.