- #1
user079622
- 299
- 20
Does wing really fly in already downward moving air?
Video from 18:15 - 19:40
Video from 18:15 - 19:40
If wing fly in own downwash, that would mean air ahead of the wing already moving downward.boneh3ad said:I don't understand the question.
Because I see upward movement of air ahead of wing...not downward..boneh3ad said:So, sure, some of that induced flow over a finite wing is downward, reducing lift.
Why are you asking me, though?
That's an airfoil, not a wing. It's 2-dimensional. The downwash is a 3-D wing effect that doesn't occur in this 2-D case.user079622 said:Because I see upward movement of air ahead of wing...not downward..
View attachment 337150
OK just reduce this upwash a little but and you get picture for wing.russ_watters said:That's an airfoil, not a wing. It's 2-dimensional. The downwash is a 3-D wing effect that doesn't occur in this 2-D case.
russ_watters said:That's an airfoil, not a wing. It's 2-dimensional. The downwash is a 3-D wing effect that doesn't occur in this 2-D case.
The image in your OP shows wingtip vortices. Is that what you are asking about? In 2-D you don't have any beginning or end of your wing.user079622 said:OK just reduce this upwash a little but and you get picture for wing.
Or you want to say that air moves downward ahead of wing ?
The flow isn't uniform across the span, so I'd say there's no general answer for the question. I suspect there is upwards flow in front of parts of the wing and downwards flow in front of other parts. But I don't think I've seen a 3D representation of the flow field.user079622 said:OK just reduce this upwash a little but and you get picture for wing.
Or you want to say that air moves downward ahead of wing ?
This is upwash ahead of wing for different aspect ratios.FactChecker said:The net downward flow of the air is the cause of lift. But that is primarily aft of the wing. The wing is the cause of the downflow and does not have the same effect of a wing in a downflow from following another airplane. So not all downflows are the same.
russ_watters said:That's an airfoil, not a wing.
Downwash refers to the downward deflection of air that occurs as a wing generates lift. When a wing pushes air downwards, the reaction forces from the air push the wing upwards, which is what we recognize as lift. The air that is pushed downwards behind the wing is known as downwash.
No, a wing does not fly in its own downwash. The wing itself generates downwash behind it as a result of the lift production, but the wing operates in the airflow that is coming towards it, which is not yet affected by the downwash. The downwash effect is observed behind the wing, influencing the airflow around the tail of the aircraft more than the wing itself.
Downwash can affect the performance of an aircraft in several ways. Primarily, it can influence the efficiency of the lift generated by the wing and the stability of the aircraft. Downwash flowing over the tail surfaces can reduce the effectiveness of these surfaces, requiring adjustments in aircraft design or control inputs to maintain stability and control. Additionally, increased downwash can lead to greater induced drag, which can reduce the overall aerodynamic efficiency of the aircraft.
While downwash is generally associated with negative effects like increased drag, it can have beneficial aspects as well. For example, in certain aircraft configurations, such as biplanes or triplanes, the downwash from an upper wing can positively influence the airflow over a lower wing, potentially enhancing lift. Moreover, in formations like those used by migrating birds or military aircraft, downwash can be exploited to reduce the drag on trailing aircraft or birds, improving the overall efficiency of the group.
Yes, aircraft designers use several techniques to minimize the negative effects of downwash. One common approach is the design of winglets at the tips of the wings, which can help to reduce the vortex strength and thereby decrease the downwash and associated induced drag. Another approach is optimizing the tail design and placement relative to the wing to ensure that the tail operates in cleaner, less disturbed air, thus maintaining control effectiveness and reducing drag.