3D Flow Field Measurements using Aerosol Correlation Velocimetry

AeroMancer Technology proposes to develop a 3D Lidar Global Airspeed Sensor (3D-GLAS) for remote optical sensing of three-component airspeeds in wind tunnel applications. Current methods of non-intrusive airspeed measurement include techniques such as Laser Doppler Velocimetry (LDV), Particle Imaging Velocimetry (PIV) and Doppler Global Velocimetry (DGV). However, some common drawbacks of all these standoff methods for 3D airspeed sensing are that they require precise alignment of separate transmitters and receivers; and it is expensive and unwieldy to extend these measurements to a large enough volume to be practical for use in medium and large wind tunnels. The proposed instrument uses range-resolved elastic backscatter data from a lidar beam that is scanned over the volume of interest to generate a 3D map of aerosol density in a short time span. Aerosol density fluctuations are cross-correlated between successive scans to obtain the displacements of the aerosol features along the three axes. Thereby, temporally and spatially resolved velocity measurements are possible at high resolution. In Phase 1, AeroMancer proposes to conduct a requirements analysis to identify the functional and operational needs of wind tunnel application and of the instrument. A signal link budget analysis tool of the proposed lidar will be developed to aid in instrument design and scaling. A conceptual design of the instrument will be developed, where the system architecture and main components will be identified. The preliminary design of the software for extraction of 3D airspeed information from the lidar data will be developed. The design studies will be supported using experimental tests with a previously developed lower-fidelity prototype of a different configuration.