We will take advantage of recent advancements in laser technology to explore new measurement techniques for NASA's wind tunnel facilities. Femtosecond (fs) lasers are 100,000x shorter pulse than typical 10 ns pulse lasers resulting in much higher power than existing previously laser technology. Can generates nonlinear effects: FLEET and FS CARS (FLEET = Femtosecond laser electronic excitation and tagging; CARS = Coherent anti-Stokes Raman Spectroscopy). Can use these techniques to measure velocity, temperature, pressure or density in wind tunnel flows with unprecedented precision accuracy. FLEET works very well in high pressure, low temperature N2 flows, such as our NTF. Such measurements will provide knowledge about flowfields as well as quantitative data for comparison with computations of the flow.
More »We are already using the FLEET technique to help NASA researchers better understand a flow-control device (swept jet actuator) which is being used in NASA's FAST-MAC project. FLEET could potentially be used in future FAST-MAC-type tests in NTF where the performance of the actuator can be evaluated in-situ for flow control. The technique could clearly show flow separation control, for example. While this project focuses on understanding and developing the physics to improve this new instrumentation, two parallel efforts (described in the comments section) are aimed at implementing the FLEET technology in NASA's large tunnels, including the National Transonic Facility. The technology is also highly relevant for supersonic and hypersonic applications where the technology can be used to characterize facilities and to study entry vehicles. The FS CARS pressure measurement capability, on the other hand, can be used to study sonic boom mitigation on supersonic aircraft.
More »Organizations Performing Work | Role | Type | Location |
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Langley Research Center (LaRC) | Lead Organization | NASA Center | Hampton, Virginia |
George Washington University | Supporting Organization | Academia | Washington, District of Columbia |
Princeton University | Supporting Organization | Academia | Princeton, New Jersey |
Sandia National Laboratories (SNL) | Supporting Organization | FFRDC/UARC | Albuquerque, New Mexico |