Distributed Position Sensing for 3D Surface Deformation in Wind Tunnels

High-definition fiber optic sensing will enable accurate, real-time 3D measurement of position, attitude, and surface deformation of surfaces in wind tunnel environments. Luna’s position sensing cable measures its 3D position and orientation, distributed along its length with a spatial resolution of less than a tenth of a millimeter. Embedded in the surface of the test model, the sensor does not impede air flow quality. The sensor cable enters the wind tunnel environment through a single aperture as small as two millimeters in diameter, and integrates directly with the existing sting fixture, with minimal invasion to the wind tunnel surface. Unlike an imaging approach, Luna’s technique is immune to refractive index change in the flow field. During Phase I, Luna developed advanced fiber optic position sensing algorithms and calibration processes obtaining positional accuracy smaller than one millimeter. Luna demonstrated surface deformation measurement of position and attitude on a laboratory scale model. During Phase II, Luna will implement the advanced sensing methods to increase sensor length. Luna will develop methods for integration of the fiber sensor into wind tunnel models. A software interface will be developed for monitoring model deformation. Luna will demonstrate a prototype system for real-time measurement.