100-kHz Burst-Mode Particle Image Velocimetry: Space-Time Correlations and Considerations for Spatial and Temporal Resolution

摘要

100-kHz particle image velocimetry is demonstrated using a double-pulsed burst-mode laser with record length of 100 ms. Pulse doublets with inter-pulse spacing of 1-5 μs and repetition rate of 100 kHz are generated using a fiber-based oscillator and amplified through an all-diode pumped burst-mode amplifier. Pre-compensation of oscillator pulse width and pulse intensity enable control of output pulse energy even for unequally spaced pulse sequences. Spatial and temporal resolution of the velocity measurements is quantified and demonstrated to be sufficient for investigating space-time correlations in highly turbulent diffusion jets with jet-diameter Reynold's Numbers from 14,000-43,000. Quantitative assesments of standard integral time and length scale definitions are made along with highly resolved space-time correlations and compared with Taylor's Frozen Turbulence Hypothesis for turbulent flows.