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How is wind turbine blade tested in Wind Tunnel?
I am working on the design & manufacture of small scale wind turbine. I need help in determining the size of model should i get manufactured for testing in the wind tunnel for its accuracy. What parameters are necessary while scaling down the actual blade design? In other words, what should be the ratio of model size to the internal cross-sectional area of wind tunnel?
For best results you make the biggest model that will fit in the tunnel.
But a turbine blade is a special problem for testing because when it is working, its airfoil has different relative speeds to the same wind because the root is moving sideways at one linear speed while the tip is traveling across the wind a 5-10-15 times as fast.
If a large model of a single blade is tested in a tunnel, even being set at different angles of attack, the results are probably not continuous. And if a small model is tested, errors as a percent get much larger.
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