Pulse-Burst PIV in a High-Speed Wind Tunnel

In recent years, time-resolved particle image velocimetry (TR-PIV) has evolved as a means of measuring temporally correlated velocity fields, allowing the acquisition of PIV movies. Extension beyond roughly 10 kHz is not yet feasible with the diode-pumped solid-state lasers that typically are used in lower speed regimes. Instead, TR-PIV in high-speed flows is best accomplished using a pulse-burst laser, as this is the only light source capable of producing sufficient energy at the necessary pulse rates. Furthermore, it can produce pairs of pulses at arbitrary separation times, which allows the very short times between paired exposures compatible with high-speed flow, in contrast with the long time between exposures using a single kHz-rate laser. Simultaneous with the maturation of pulse-burst laser technology, quality high-speed cameras have begun to achieve desirable framing rates without excessive sacrifice of the size of the spatial array.