The technical objectives of this proposed work are to develop and prove the use of LDV and CompLDV for particle-position-resolving and flow velocity profile measurements using small sub-micron particles or facility-residual particles in higher speed test flows, making use of new hardware capabilities, miniature optical probe head designs for versatile use in facilities and models, and signal processing techniques that have not been simultaneously implemented. With the optical system feature, the expected results from this multi-SBIR-Phase work are improved low-collected-light LDV technology and a completely functional multi-velocity-component CompLDV system that can be used with only facility residual or small sub-micron seeding particles in low-speed and high-speed flow facilities for low uncertainty particle position and low uncertainty velocity profile measurements. Methods to generate 50 to 200 nanometer particles and clean evaporating particles for in situ local seeding in flow facilities appear to be possible and need to be examined for practical implementation in NASA facilities. Phase-Doppler anemometry signal processing will be used to determine the size of larger particles. The known measurement volume fringe light intensity variation for the LDV and CompLDV and light scattering theory also will be used to determine an estimate of particle size.

When completed under a Phase II or Phase III, this small sub-micron particle or facility residual particle non-intrusive multi- velocity-component spatially-resolving LDV and CompLDV velocity profile measurement system with miniature probe heads that can fit inside models will enhance NASA Aeronautics Ground Test and Measurements Technologies, require minimal small sub-micron seeding methods that do not contaminate wind tunnel walls or anti-turbulence screens, enable more routine measurements for advanced computational simulations, even for low-temperature facilities, such as the National Transonic Facility (NTF) and hypersonic facilities, increase data capture per test point, including the ability to simultaneously measure multiple flow parameters at high acquisition rates and capture rapidly evolving or oscillatory flow phenomena, improve current particle-based diagnostics and produce significant measurement accuracy enhancements. A Phase II product with low uncertainty velocity profile measurements will solve a specific difficult problem for the National Transonic Facility (NTF), the determination of flow angles during semi-span testing. Based on recent past improvements, the resulting measurement system will be robust and user-friendly for practical and routine applications.

It is clear that other groups involved with measuring high-speed flows or flows without additional added seed or clean seed will be interested in using these new developments. Universities, DoD laboratories, aircraft and aircraft engine manufacturers R&D laboratories should be interested in acquiring systems. One US company has already expressed intense interest in the final product. In the past, AUR has sold the existing models of LDV and CompLDV systems to these potential customers of the Phases II and III small sub-micron particle/residual particle LDV and CompLDV system.