Development of Filtered Rayleigh Scattering Velocimetry for Wind Tunnel Application.
Final rept. 14 Apr 97-13 Jan 98
INNOVATIVE SCIENTIFIC SOLUTIONS INC BEAVERCREEK OH
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THIS REPORT DEVELOPED UNDER SBIR CONTRACT The goal of this SBIR program was to develop a FRS filtered Rayleigh scattering velocimetry instrument for the study of unsteady flow fields. During Phase I we constructed a single-velocity-component device for use with a single-mode Q-switched NdYAG laser. This ERS device included a custom wavemeter for recording accurately the laser wavelength on each pulse, two 16-bit, back-illuminated CCD cameras, and custom Windows-95 software for integrating the wavemeter and cameras. Initially, we tested and debugged the FRS system using a supersonic Mach 1. 36 axisymmetric jet. These tests demonstrated that accurate mean within 5 and instantaneous within 4 velocities can be obtained with this technique. Subsequent to these tests, we implemented the FRS velocimetry instrument in the SARL Subsonic Aerodynamic Research Laboratory wind tunnel to test the feasibility of applying this advanced instrumentation in a realistic large-scale tunnel facility. We investigated the flow over a delta-wing model with and without tail fins here, the freestream velocity compared well to the value derived from pitot probes, while FRS measurements over the delta wing provided new insight into complex, unsteady flows. Potential applications include the timely and cost-efficient testing of novel aerodynamic concepts and designs in large-scale wind tunnels.
- Fluid Mechanics