Distributed Anemometry via High-Definition Fiber Optic Sensing

Luna is developing a distributed anemometer that can directly measure flow field velocity profiles using high-definition fiber optic sensing (HD-FOS). The concept is inspired by hot-film anemometry, but extends the capability from a point measurement to a distributed measurement. With a spatial resolution of 1.25 mm, thousands of data points can be collected along an optical fiber to enable 1D, 2D or 3D field measurements, depending on the routing of the sensor. The benefits of this approach compared to particle image velocimetry (PIV) include: no seeding of the flow is necessary; the sensor can be used in non-line-of-sight locations; velocity and temperature profiles can simultaneously be acquired; and the technology can potentially be implemented in a flying vehicle. Measurements of boundary layer velocity and temperature profiles, transition location, and skin friction can be attained with this technique. Phase I will prove the feasibility of flow velocity measurement from a distributed fiber optic sensor over a range of temperatures and Mach numbers to quantify its accuracy. During Phase II, the technology will be matured for implementation in NASA wind tunnels and commercial jet engines. During Phase III, Luna will work with NASA and industry partners to commercialize the technology.