Proper Orthogonal Decomposition based 3D microPIV: Application to electrothermal flow study

Since late 1990\u92s, micron-resolution particle image velocimetry (?PIV) has been widely developed to measure fluid flow velocities field in microchannels [1]. While 2D ?PIV method has been extensively investigated, accurate 3D ?PIV still remains challenging to implement since it usually requires specialized and expensive equipments (e.g. confocal, stereo imaging or holography microscopes) [2]. In the present work, the out-of-plane velocity component w is reconstructed from in-plane components (u,v), using fluid incompressibility. We use Proper Orthogonal Decomposition (POD) to decompose u and v into its dominant n eigenfunctions ånk =1 ak(z)fk(x;y) thereby filtering noise and simplifying the signal. In addition, those eigenfunctions are well suited to solve incompressibility equation since they enable independent differentiation and integration. Our method is applied to an AC electrothermal fluid flow, which was previously studied experimentally and numerically[3]