Integration of synchronised IR and PIV unsteady measurements on a channel flow

Estimating velocity fields in wall-bounded turbulent flows using non-intrusive, wall-based measurements is a crucial challenge with significant implications for fundamental research and engineering applications like flow control. Traditional methods often rely on technically demanding intrusive probes or numerical simulations, which can be difficult to translate to real-world experimental setups. This study introduces a robust, non-intrusive experimental platform that uses infrared thermography with a heated thin-foil sensor to capture high-resolution, time-resolved measurements of unsteady heat transfer on a channel wall. These measurements are synchronized with particle image velocimetry data to enable the simultaneous acquisition of near-wall velocity fields. The methodology addresses key experimental challenges, including a low signal-to-noise ratio and the need for high-frequency acquisition. We demonstrate that the acquired heat transfer fluctuations show strong spatial and temporal coherence with near-wall structures, supporting their use for velocity field estimation. This work establishes a framework for generating reliable, synchronized datasets, paving the way for the development and validation of data-driven velocity field estimators and advanced active flow control strategies under realistic experimental conditions.