Abstract
Numerical calculations of the flow around and past a heaving airfoil were conducted using an open source CFD code, OpenFOAM. The vorticity field downstream of the airfoil is decomposed into several low-order modes by applying proper orthogonal decomposition (POD) method in order to evaluate quantitatively the vortical structure in the wake. The cumulative contribution for each eigenvalue and the eigenfunction contours for a first few low-order modes were investigated for several test cases of varying the dimensionless amplitude h and the Strouhal number St of the airfoil oscillation. It is found that the low-order mode becomes more dominant as h decreases while the enstrophy contribution for higher mode grows as St decreases.
