Laser-Induced Thermal Acoustics (LITA) has been used to measure the flow field in the slat region of a two-dimensional, high-lift system in the NASA Langley Basic Aerodynamics Research Tunnel (BART). Unlike other point-wise, non-intrusive measurement techniques, LITA does not require the addition of molecular or particulate seed to the flow. This provides an opportunity to obtain additional insight and detailed flow-field information in complex flows where seeding may be insufficient or detection is problematic. Based on the successful use of LITA to measure the flow over a backward-facing step, the goal of this study was to further evaluate the technique by applying it to a more relevant and challenging flow field such as the slat wake on a high-lift system. Streamwise velocities were measured in the slat wake and over the main element at 11.3 degrees angle of attack and a freestream Mach Number of 0.17. The single-component LITA system is described and velocity profiles obtained using LITA are compared to profiles obtained using two-dimensional, Digital Particle Image Velocimetry (DPIV) and a steady, Reynolds-Averaged Navier-Stokes (RANS) flow solver for the same configuration. The normalized data show good agreement where the number of measurement locations had sufficient density to capture the pertinent flow phenomena.
Projection Moire Interferometry (PMI) has been used to measure the structural deformation of micro air vehicle (MAV) wings during a series of wind tunnel tests. The MAV wings had a highly flexible wing structure, generically reminiscent of a bat's wing, which resulted in significant changes in wing shape as a function of MAV angle-of-attack and simulated flight speed. This flow-adaptable wing deformation is thought to provide enhanced vehicle stability and wind gust alleviation compared to rigid wing designs. Investigation of the potential aerodynamic benefits of a flexible MAV wing required measurement of the wing shape under aerodynamic loads. PMI was used to quantify the aerodynamically induced changes in wing shape for three MAV wings having different structural designs and stiffness characteristics. This paper describes the PMI technique, its application to MAV testing, and presents a portion of the PMI data acquired for the three different MAV wings tested.