Unformatted text preview: Lecture F05 Mud: Intro to 3-D Wings 1. What exactly is downwash? (1 student) A vertical velocity component which is due to the presence of the tip vortices. If the wing has infinite span (is 2-D), there are no vortices and no downwash. 2. Why do we look at only the vertical z-velocity of the vortex, and not the horizontal y-velocity? (1 student) Only the vertical component affects the velocity triangle and the angle of attack in the x- z airfoil plane. 3. How do the vortices affect the ﬂow in front of the wing? (1 student) The vortices do have downwash ahead of the wing, but it rapidly decays to zero as we move upstream. 4. Does the downwash have any affect below the wing? (1 student) The downwash is maximum directly behind the wing, and gradually dies off to zero as we go up or down. 5. How do you design a plane to minimize the downwash? (1 student) The surest way is to increase the span, but this has other drawbacks. In the UE Dragonﬂy competition you will be looking at these tradeoffs.tradeoffs....
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- Fall '05
- Aerodynamics, Wing, Lift, Downwash, x-z airfoil plane