Model-based fusion of PIV and hot-wire measurements for reconstruction of wall-bounded turbulent flows

Laboratory instrumentation is often limited in its ability to fully resolve the spatio-temporal fluctuations associated with turbulent flows. Particle Image Velocimetry (PIV) systems capable of fine spatial resolution are often limited to low temporal resolution, while instruments capable of high temporal resolution (e.g., hot wire anemometers) are restricted to point measurements. In this study, we employ models derived directly from the governing Navier-Stokes equations to reconstruct velocity fields in the intermediate time horizon between non-time resolved PIV snapshots, with input from time-resolved point measurements. Models grounded in rapid distortion theory are used to integrate the velocity field both forwards and backwards in time from the PIV snapshots to generate flow field predictions at high spatio-temporal resolution. Point measurements are then used to estimate the relative weights of the forward- and backward-time predictions. Direct numerical simulation data for turbulent channel flow from the Johns Hopkins Database is used to validate the sensor fusion approach, and to evaluate reconstruction accuracy. As proof-of-concept for real-world systems, this framework is also being used to reconstruct flow fields for ongoing turbulent boundary layer experiments.