Main results of the analysis of the HOMER Lagrangian Particle Tracking and Data Assimilation database

Abstract

This contribution discusses the work conducted within the HOMER task 2.4 “Method Performance Assessment and Experiment Design Rules”. In particular, we present the comparative assessment of different Lagrangian Particle Tracking (LPT) and Data Assimilation (DA) algorithms for the case of a turbulent wall-bounded flow interacting with a moving panel. Within task 2.1 “Numerical Benchmark Datasets: Turbulent Boundary Layer–Panel Interaction”, a synthetic experiment at a significant image noise level is performed that reproduces the air flow around a cylinder (D = 1 cm) in ground effect, whereby a flexible panel is placed undergoing periodic oscillations. The database comprises two different panel materials, namely metal and rubber, different marker densities on the panel’s surface and different concentrations of tracer particles in the flow. Images of the flow tracers and of the surface markers are acquired either with a four-camera volumetric imaging setup or with a dual setup composed of four LPT cameras and two Digital Image Correlation (DIC) cameras. Additionally, three image acquisition modes are simulated, namely time-resolved (TR), twopulse (TP) and four-pulse (FP). The data are analysed in terms of percentages of correctly reconstructed, missed and ghost particles, errors of the measured particles’ positions, velocities and accelerations (LPT analysis) and errors of the reconstructed flow fields, panel’s positions and surface pressures (DA analysis).