Stereoscopic particle image velocimetry of laser energy deposition on a mach 3.4 flow field

Abstract

Experiments were performed within Rutgers University’s supersonic wind tunnel to measure the influence of off-axis laser energy deposition on the flow field about an ogive cylinder at a freestream Mach number of 3.4. Perturbation of the flow field was accomplished using an infrared laser source, focused to a point ahead of the ogive cylinder. Stereoscopic particle image velocimetry measurements were performed to quantify the effects of energy deposition on the flow field at discrete time delays following the generation of the spark. The SPIV results showed a measurable change in streamwise velocity downstream of ogive’s shock that appears to be dependent on proximity of the initial spark to the ogive’s surface. In contrast, the spark was shown to have little influence on the vertical velocity component at early times. Data corresponding to later times showed the passage of an induced jet through the flow field. The jet rotated about its axis while passing through the shock structure, in agreement with previous qualitative imaging. These results demonstrate the feasibility of using SPIV to investigate the influence of laser energy deposition on the flow field.