Near-Field Velocity Measurement System for Wind Tunnel Testing

ABSTRACT: Significant advances to subminiature three-velocity component laser-Doppler velocimetry (SM3LDV) technologies developed through the AEDC SBIR program will be implemented using technologies and resources from several groups. The transition activities address five needs. A new more compact optical probe for 16T will be enabled by leveraging coherent laser behavior to obtain three-velocity component measurements with excellent spatial resolution through a single transceiver lens design. Second, to avoid the long fiber optics cables required for the SM3LDV for use in the 16T wind tunnel exhibit non-linear phenomena that significantly degrade probe performance, an environment chamber will be constructed to house the photonics cart within the pressure vessel of 16T and reduce test times in the 16T when using the SM3LDV. Third, the AUR Studio software, largely developed through AEDC SBIR funding, will be upgraded for more ease of post-processing, saving the customer significant labor time for preparation of final test results. To address other needs of the US Air Force, a novel compact probe and linear/rotary traverse system will be developed under this effort for low speed wind tunnel applications at AFRL at WPAFB. Finally, the photodetector package will be improved for immunity to radio frequency interference and for response beyond 500MHz. BENEFIT: The SM3LDV implemented into the PWT 16T wind tunnel is a new capability not available at any other facility at the Reynolds number and Mach number conditions achievable. The improvements proposed would greatly improve the reliability of the current technology as well as reducing costs by reducing the amount of time required to analyze test data.