Reconstruction of reduced-order EHD flow fields using the proper orthogonal decomposition

The proper orthogonal decomposition (POD) algorithm was applied to reconstruct the instantaneous velocity field of the EHD jet in this work. Particle image velocimetry (PIV) measurements were conducted on EHD jets in a bladeplane configuration at different voltages and electrode spacings. The acquired instantaneous flow fields were used as input to yield the orthogonal spatial modes, the temporal coefficients and the eigenvalues that are automatically ranked by kinetic energy magnitudes. It is shown that the dominant spatial modes obtained by POD usually correspond to large-scale coherent structures, while the higher modes characterize finer-scale turbulent vortex structures. Although POD-based flow field reconstruction allows for the elimination of non-coherent noise and spurious vectors in the original PIV data, the number of modes available for reconstructing the instantaneous flow field tends to increase due to the decrease in the energy content of the dominant modes.