Development of a Dual-PIV system for high-speed flow applications

International audienceA new Dual-Particle Image Velocimetry (Dual-PIV) system for application in supersonic flows was developed. The system was designed for shock-wave/ turbulent boundary layer interactions with separation. This type of flow places demanding requirements on the system, from the large range of characteristic frequencies O(100 Hz −100 kHz) to spatial and temporal resolutions necessary for the measurement of turbulent quantities [1-3]. While classic PIV systems using high resolution CCD sensors allow high spatial resolution, these systems cannot provide the required temporal resolution. Existing high-speed PIV systems provide temporal and CMOS sensor resolutions, and even laser pulse energies, that are not adapted to our needs. The only obvious solution allowing sufficiently high spatial resolution, access to high frequencies, and a high laser pulse energy is a multi-frame system: a Dual-PIV system, consisting of two synchronized PIV systems observing the same field of view, will give access to temporal characteristics of the flow. The key technology of our system is frequency-based image separation: two lasers of different wave lengths illuminate the field of view. The cross-pollution with laser light from the r