| Autor: |
Dustin L. Grissom, William J. Devenport |
| Rok vydání: |
2004 |
| Předmět: |
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| Zdroj: |
10th AIAA/CEAS Aeroacoustics Conference. |
| DOI: |
10.2514/6.2004-2956 |
| Popis: |
*† A computerized gust generator has been developed and tested for the Virginia Tech Stability Wind Tunnel. The generator consists of 10 airfoil section vanes spanning from the top to the bottom of the tunnel contraction. Computer controlled stepper motors drive the vanes independently to create deterministic disturbances. Three component hot wire velocity measurements show that the generator is capable of creating both continuous sinusoidal and impulsive upwash disturbance patterns. The impulsive disturbances can be scaled in amplitude to as much as 35% of the freestream flow speed, and as short as 0.04 seconds in period. Impulsive disturbances of less than 20% of the freestream speed are stable for the length of the test section (7 meters). Aerodynamic disturbances created by the generator are repeatable and consistent in shape, size, and arrival time. Ensemble averaging of repeated disturbances can reduce experimental uncertainty while retaining all time domain information. This approach allows time domain analysis of a system’s aerodynamic response to a disturbance instead of a statistical analysis. Experimental results are compared with theoretical predictions based on a discrete vortex model. The model uses fixed vortices to represent the grid elements and a series of free vortices to model their wakes. These comparisons show qualitative agreement in the flow pattern, and predict some of the nonlinear behavior seen in the disturbances. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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