Near-wall 3D Lagrangian Particle Tracking over a 6:1 prolate spheroid at up to Re = 12 Million

The High-Reynolds Number Prolate Spheroid (HIPRO) program focuses on providing high-fidelity measurements on a 6:1 prolate spheroid. Reynolds number values range from 4.2 x 10^6 to 12.3 × 10^6, where the former is compared to existing literature and the latter is an unprecedented test case which achieves viscous lengthscales below 10 µm. The anodized aluminum model measures 3 meters in length, is pitched from 0 to 20° angle of attack, and rolled from +180 to -180°. Near-wall 3D velocity fields are obtained at 24% of the model's length through the use of an in-situ local injection of fluorescent particles and Lagrangian particle tracking (LPT) algorithms. The physical space allocated to this system was confined to 333 mm in length, 175 mm in width, and 127 mm in height. In addressing this constraint, a novel compact plenoptic imager was designed that also delivers light from within the model. A green laser (527nm) is directed through a fiber optic ring light and reflected off a parabolic mirror to provide a shallow darkfield illumination of the measurement volume. The custom viewport is made of a polymer refractive-index-matched to water to reduce the distortion of the spheroid's curved surface. Preliminary results will be shown.