Conceptual Design of a Laser Light Sheet Flow Visualization System for a Pressurized, Low Speed Wind Tunnel

Abstract

The conceptual design and component validation of a laser light sheet flow visualization system for the QinetiQ 5m wind tunnel was conducted over the last two years by the Testing Methods Group of Boeing Commercial Airplanes. The purpose of this system is to complement wind tunnel force and pressure data by helping visualize off-body aerodynamic phenomena affecting model performance to help diagnose discrepancies between experimental and computational results. Smoke seeding and laser diagnostics are commonplace in many wind tunnels around the world. However, the requirement that this system be robust and user friendly enough to operate quickly and reliably in a high Reynolds number, large scale, low speed wind tunnel environment make this a unique and complex system. Each of the 4 major system components (laser, optics, seeding, and dispensing) were researched in detail and candidate system components were identified. In addition, two wind tunnel tests were conducted in a smaller, open circuit low speed wind tunnel to validate some of the findings and to prototype candidate hardware.