Wall to wall airfoil in a wind tunnel

In summary, downwash can occur in a tall wind tunnel with wall to wall airfoil due to the diversion of air flow downwards, despite the presence of walls preventing air circulation.
  • #1
John Mcrain
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Does wall to wall airfoil produce downwash in wind tunnel ?
 
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  • #2
Depends if the wind tunnel has a ceiling and a floor, and if it does, how close to the ceiling and floor are to each other. If the wind tunnel is vertically "short", only a tiny amount of downwash occurs as air flows across the wing. For example, the amount of downwash over an airfoil with a 1 foot chord in a 1 foot tall wind tunnel will be tiny, while the amount downwash from that same air foil with a 1 foot chord in a 20 foot tall wind tunnel will be significant.
 
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  • #3
rcgldr said:
Depends if the wind tunnel has a ceiling and a floor, and if it does, how close to the ceiling and floor are to each other. If the wind tunnel is vertically "short", only a tiny amount of downwash occurs as air flows across the wing. For example, the amount of downwash over an airfoil with a 1 foot chord in a 1 foot tall wind tunnel will be tiny, while the amount downwash from that same air foil with a 1 foot chord in a 20 foot tall wind tunnel will be significant.
Wall to wall airfoil has "wingspan" same as wind tunnel width, high pressure can't leak to low pressure at tips.No wingtip vortices.
In wall to wall airfoil in closed test section downward movement of air will create a void above it(walls/vacuum stop this action), and the air below has to make place for that downward moving air,but again walls stop this action.
How then this is possible in fully closed wind tunnel even test section is very big/tall compare to airfoil?
Upper(ceiling) and lower(floor) walls don't allow that air circulation which downwash requier.
downwash .jpg.png
You say that downwash(like this on picture below) is possible in tall wind tunnel for wall to wall airfoil.
* to make that possible ,air behind center of airfoil must go down and air at side walls must go up,this air circulation must produce two roll-up vortices,Why I don't see described air DOWNWARD MOVEMENT in any wall to wall airfoil wind tunnel video?
cyr0c.jpg
downwash behind wing video:
https://fyfluiddynamics.com/2014/04/Newtons-third-law-says-that-forces-come-in-equal/
 
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  • #4
John Mcrain said:
Wall to wall airfoil has "wingspan" same as wind tunnel width, high pressure can't leak to low pressure at tips.No wingtip vortices.
In wall to wall airfoil in closed test section downward movement of air will create a void above it(walls/vacuum stop this action), and the air below has to make place for that downward moving air,but again walls stop this action. How then this is possible in fully closed wind tunnel even test section is very big/tall compare to airfoil?
Upper(ceiling) and lower(floor) walls don't allow that air circulation which downwash requires.
A fresh stream of air is flowing into the wind tunnel. For a tall wind tunnel, in order for a pressure differential to be created, part of that air flow has to be diverted downwards, it will eventually recover, but there will be downwash in the vicinity of the wing.
 

Related to Wall to wall airfoil in a wind tunnel

1. What is a wall to wall airfoil in a wind tunnel?

A wall to wall airfoil is a type of airfoil shape that is used in wind tunnels for aerodynamic testing. It is designed to mimic the shape and behavior of an airfoil in real-life conditions, allowing scientists to gather data and make predictions about the performance of an object or aircraft.

2. How does a wall to wall airfoil work in a wind tunnel?

In a wind tunnel, a wall to wall airfoil is placed in the path of a controlled and consistent airflow. This airflow creates lift and drag forces on the airfoil, which can be measured and analyzed by scientists. The data collected can then be used to improve the design and performance of aircraft and other objects that utilize airfoils.

3. What are the benefits of using a wall to wall airfoil in a wind tunnel?

Using a wall to wall airfoil in a wind tunnel allows for precise and controlled testing of aerodynamic properties. This can help scientists and engineers make more accurate predictions and improve the design of aircraft, reducing drag and increasing efficiency. It also allows for testing in a controlled environment, eliminating external factors that may affect the results.

4. How is a wall to wall airfoil different from other airfoil shapes?

A wall to wall airfoil is unique in that it extends from one wall of the wind tunnel to the other, creating a continuous surface for airflow to pass over. This allows for more accurate and consistent data collection, as well as the ability to test larger airfoil designs. Other airfoil shapes may only cover a portion of the wind tunnel, leading to less precise results.

5. What are some real-world applications of studying wall to wall airfoils in a wind tunnel?

Studying wall to wall airfoils in a wind tunnel has many practical applications, particularly in the field of aeronautics. The data collected can be used to improve the design and efficiency of aircraft, as well as other objects that utilize airfoils such as wind turbines. It can also aid in the development of new technologies and materials for use in the aerospace industry.

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